Control Recipients Research Articles

Cigarette smoke-induced disordered microbiota aggravates the severity of influenza A virus infection.

Cigarette smoke (CS) promotes the development of chronic pulmonary disease and has been associated with increased risk for influenza-related illness. Here, we directly addressed the impact of CS disordered microbiota on the severity of influenza A virus (IAV) infection. Specific and opportunistic pathogen-free (SOPF) C57BL/6J mice were exposed to CS or room air (RA) for 5.5 months. Each exposed mouse was then cohoused with a group of recipient germ-free (GF) mice for 1 month for microbial transfer. Colonized GF mice were then infected intranasally with IAV and disease development was monitored. Upper and lower airway and fecal microbiota were longitudinally investigated by 16S rRNA gene sequencing and bacterial cultures in donor and recipient mice. The bacterial family Streptococcaceae accounted for the largest difference between CS- and RA-exposed microbiota in the oropharynx. Analysis of the oropharynx and fecal microbiota indicated an efficient transfer to coprophagic recipient mice, which replicated the differences in microbiota composition observed in donor mice. Subsequent IAV infection revealed significantly higher weight loss for CS microbiota recipient mice at 8-10 days post infection (dpi) compared to control recipient mice. In addition, H1N1 infection inflicted substantial changes in the microbiota composition, especially at days 4 and 8 after infection. In conclusion, mice with a CS-associated microbiota suffer from higher disease severity upon IAV infection compared to mice colonized with a normal SOPF microbiota. Our data suggest that independently of CS exposure and concomitant structural lung damage, microbial distortion due to CS exposure may impact the severity of IAV disease course.IMPORTANCEIt has been reported that chronic exposure to CS is associated with a disordered microbiota composition. In this study, we colonized germ-free (GF) mice with the microbiota from SOPF mice which were chronically exposed to CS or RA. This allowed disentangling the effect of the disordered microbiota from the immune-modulating effects of actual CS exposure. We observed a successful transfer of the microbiotas after cohousing including specific microbiota differences induced by CS exposure in formerly GF mice, which were never exposed to CS. We then investigated the effects of IAV infection on the disease course and microbiotas of formerly GF mice. We found that mice with CS-associated microbiota reveal worse disease course compared to the control group. We hypothesize that CS-induced disordering of the microbiota may, indeed, impact the severity of influenza A disease.

An Evaluation of Skin and Immunological Responses after Using a Novel Cross-Linked Porcine-Based Dermal Injectable Collagen with Lidocaine for Nasolabial Fold Correction.

Background: Hypersensitivity to the new dermal injectable porcine-based collagen with lidocaine featuring a novel cross-linking technology (test filler) for nasolabial fold correction was compared to the commercially available traditional cross-linked dermal injectable porcine-based collagen with lidocaine (control filler). Methods: Recruited participants (n = 279) received a single 0.1 mL intradermal injection of either test filler or control filler in the left forearm as a screening skin allergy test. Injection sites were assessed clinically at 24 h post-implant. Treatment was given to 252 successfully screened participants, and injection sites were monitored for 21 days. Immunological examinations were performed at screening and then at 4 and 24 weeks post-treatment. Observations for adverse events continued until the 52nd week. Results: Intradermal allergy testing results were negative for all the test recipients (0/124) and positive for two control recipients (2/132, 1.5%). Most of the participants exhibited no changes in serum immunoglobulin (IgG, IgM) and complement (C3, C4) levels. No serious adverse events related to the device were recorded. Most adverse events were common complications of dermal filler treatment and were related to the injection site. Most adverse effects were resolved or under control by 52 weeks. Conclusions: Hypersensitivity reactions with the test filler were lower than those with the control filler, validating the safe use of test filler for nasolabial fold correction without the need for pretreatment skin testing.

Early outcomes in heart transplantation using donation after circulatory death donors in patients bridged with durable left ventricular assist devices

ObjectiveDonation after circulatory death heart transplantation potentially increases donor allografts, especially for patients with lower listing status. We assessed the outcomes of donation after circulatory death heart transplantation in patients bridged with durable left ventricular assist devices. MethodsThe United Network for Organ Sharing database was queried for adult heart transplants using donation after circulatory death donors from 2019 to 2022. Patients were stratified between those with durable left ventricular assist devices and those with intra-aortic balloon pump, inotropic, or no bridging support (control group). Primary outcome was 1-year mortality. Secondary end points were hospital length of stay, stroke, pacemaker implantation, dialysis, and acute rejection before discharge. ResultsA total of 160 left ventricular assist device recipients and 311 control recipients met study inclusion criteria. Recipients bridged with left ventricular assist devices were younger (55 vs 58 years, P < .001) with lower body mass index (28.3 vs 30.3, P < .001), longer waitlist times (112 vs 34 days, P < .001), longer out of body times (5.7 vs 4.6 hours, P < .001), and less frequent normothermic regional perfusion (31% vs 40%, P = .049). Patients with left ventricular assist devices commonly underwent transplantation at United Network for Organ Sharing status 3 and 4 (92%), whereas control patients underwent transplantation at status 2 (27%), status 3 (10%), status 4 (30%), or status 6 (30%). Kaplan–Meier analysis showed no difference in 1-year mortality between groups (P = .34). However, acute rejection was higher in the unadjusted left ventricular assist device cohort (26% vs 13%, P < .001). On multivariable logistic regression, left ventricular assist device was an independent predictor of acute rejection (odds ratio, 2.21, 95% CI, 1.32-3.69, P = .002). ConclusionsDurable left ventricular assist devices may be associated with a higher risk of developing an early inflammatory response in donation after circulatory death heart transplantation; however, 1-year survival was similar between groups.

Preconception and/or preimplantation exposure to a mixture of environmental contaminants altered fetoplacental development and placental function in a rabbit model

Pregnant women are daily exposed to environmental contaminants, including endocrine disruptors that can impact the offspring's health. This study aimed to evaluate the effects of maternal oral exposure to a mixture of contaminants at a dose mimicking women's exposure, during folliculogenesis and/or preimplantation period (FED and ED groups, respectively) on the fetoplacental phenotype in a rabbit model. The mixture (DEHP, pp’DDE, β-HCH, HCB, BDE-47, BPS, PFOS, PFOA) was defined based on data from HELIX and INMA cohorts. FED and ED females or unexposed females (control) were inseminated, their embryos were collected and transferred to unexposed control recipient rabbits at 80 h post-insemination. The effects of maternal FED and ED exposure were evaluated on fetoplacental growth and development by ultrasound, fetoplacental biometry, fetal metabolism, placental structure and function. The results demonstrated that the mixture weakly affected ultrasound measurements, as only placental volume increased significantly in FED vs ED. Analysis of placental structure demonstrated that the volume fraction of the maternal blood space was increased in FED vs control. Pre- and/or periconception exposure did not affect biometric at the end of gestation, but affected FED fetal biochemistry. Plasma triglyceride concentration was reduced compared to control. However, total cholesterol, urea, ASAT and ALAT in fetal blood were affected in both exposed groups. Multiple factor analysis, including biometric, biochemical, and stereological datasets, indicated that the three groups were significantly different. Additionally, several placental genes were differentially expressed between groups, compared two by two, in a sex-specific manner, with more difference in females than in males. The differentially expressed genes were involved in lipid, cholesterol, and drug/xenobiotic metabolism in both sexes. These results indicate that maternal exposure to environmental contaminants during crucial developmental windows only mildly impaired fetoplacental development but disturbed fetal blood biochemistry and placental gene expression with potential long-term effects on offspring phenotype.

The role of interleukin 27 in donor specific alloantibody responses

Abstract There is a great clinical need for new approaches inhibiting pathogenic donor specific alloantibodies (DSA) and antibody-mediated rejection (AMR) in transplantation. Targeting interleukin-6 (IL-6) showed modest promise for AMR treatment. Interleukin-27 (IL-27) also belongs to IL-6 cytokine family, utilizes the same receptor signaling chain, gp130, and has many overlapping functions with IL-6. The current study tested the role of IL-27 in humoral immune responses using mouse transplant models. First, B6.WT and B6.IL-27R-/- recipients (H-2b) were transplanted with BALB/c heart allografts (H-2d). By d. 21 posttransplant, B6.WT recipients developed serum DSA against donor class I and class II MHC. In contrast, DSA responses were markedly reduced in B6.IL-27R-/- recipients. We next tested how IL-27 neutralization affects DSA using mAbs against p28 IL-27 subunit. B6.WT recipients transplanted with BALB/c skin allografts and treated with mAb against either p28, IL-6, or IL-6R or control IgG for the first two weeks posttransplant. While control recipients developed anti-H-Dd DSA, none of anti-p28 mAb treated recipients generated DSA, comparable to the effects of anti-IL-6 or anti-IL-6R therapies. Anti-IL-27 mAb resulted in a more profound decrease in the numbers of antibody secreting spleen plasma cells compared to anti-IL6 and anti-IL-6R treatments. Our data identify IL-27 as a novel therapeutic target to inhibit pathogenic DSA responses in transplant recipients.

Mucosal affairs: glycosylation and expression changes of gill goblet cells and mucins in a fish-polyopisthocotylidan interaction.

Secreted mucins are highly O-glycosylated glycoproteins produced by goblet cells in mucosal epithelia. They constitute the protective viscous gel layer overlying the epithelia and are involved in pathogen recognition, adhesion and expulsion. The gill polyopisthocotylidan ectoparasite Sparicotyle chrysophrii, feeds on gilthead seabream (Sparus aurata) blood eliciting severe anemia. Control unexposed and recipient (R) gill samples of gilthead seabream experimentally infected with S. chrysophrii were obtained at six consecutive times (0, 11, 20, 32, 41, and 61 days post-exposure (dpe)). In histological samples, goblet cell numbers and their intensity of lectin labelling was registered. Expression of nine mucin genes (muc2, muc2a, muc2b, muc5a/c, muc4, muc13, muc18, muc19, imuc) and three regulatory factors involved in goblet cell differentiation (hes1, elf3, agr2) was studied by qPCR. In addition, differential expression of glycosyltransferases and glycosidases was analyzed in silico from previously obtained RNAseq datasets of S. chrysophrii-infected gilthead seabream gills with two different infection intensities. Increased goblet cell differentiation (up-regulated elf3 and agr2) leading to neutral goblet cell hyperplasia on gill lamellae of R fish gills was found from 32 dpe on, when adult parasite stages were first detected. At this time point, acute increased expression of both secreted (muc2a, muc2b, muc5a/c) and membrane-bound mucins (imuc, muc4, muc18) occurred in R gills. Mucins did not acidify during the course of infection, but their glycosylation pattern varied towards more complex glycoconjugates with sialylated, fucosylated and branched structures, according to lectin labelling and the shift of glycosyltransferase expression patterns. Gilthead seabream gill mucosal response against S. chrysophrii involved neutral mucus hypersecretion, which could contribute to worm expulsion and facilitate gas exchange to counterbalance parasite-induced hypoxia. Stress induced by the sparicotylosis condition seems to lead to changes in glycosylation characteristic of more structurally complex mucins.

Polyomavirus Nephropathy in ABO Blood Group-Incompatible Kidney Transplantation: Torque Teno Virus and Immunosuppressive Burden as an Approximation to the Problem

IntroductionEarlier reports suggest that patients after ABO-incompatible kidney transplantation (ABOi) are at enhanced risk to develop BK-virus (BKV) nephropathy (BKPyVAN). It remains elusive whether this is a result of more intense immunosuppression or an ABOi-associated ‘intrinsic attribute’. To address this question, we measured Torque-Teno-Virus (TTV) loads as a quantitative proxy for immunosuppressive depth in ABOi recipients and compared them to HLA-incompatible (HLAi, i.e. pre-transplant donor-specific antibody-positive) and standard-risk transplant recipients. MethodsOur retrospective study screened 2256 consecutive kidney transplantations performed between 2007-2020 at the Medical University of Vienna. Out of 629 in-principle eligible transplantations, we were able to include 465 patients: 42 ABOi, 106 HLAi and 317 control recipients. Longitudinal TTV- and BKV-PCR was carried out at pre-defined timepoints and ranged from pre-transplant until month 24 post-transplantation. TTV loads and immunosuppression were evaluated in the context of BKV-associated-complications. ResultsABOi recipients had a higher TTV load compared to HLAi and controls both at month three (median 1.5x109 vs. 2.4x108 vs. 9.1x107, p=0.010) and month six (3.1x109 vs. 1.4x107 vs. 6.4x107, p=0.014) post-transplantation. Tacrolimus exposure was significantly higher in ABOi patients compared to HLAi and control patients (ABOi vs. HLAi: p=0.007, ABOi vs. controls: p<0.0001). Biopsy-proven BKPyVAN was more frequent in ABOi recipients when compared to HLAi- and control-recipients (11.9% vs. 2.8% vs. 4.1%, p=0.046). ConclusionOur data support the assumption that ABOi patients are indeed at higher risk to develop BKPyVAN. A higher TTV load and immunosuppressive burden suggest that intense immunosuppression, rather than an ‘intrinsic attribute’ conferred by ABOi, may contribute to this finding.

Three-year outcomes of de novo tacrolimus extended-release tablets (LCPT) compared to twice-daily tacrolimus in adult heart transplantation

BackgroundExtended-release tacrolimus for prophylaxis of allograft rejection in heart transplant (HT) recipients is currently not FDA-approved. One such extended-release formulation of tacrolimus known as LCPT allows once-daily dosing and improves bioavailability compared to immediate-release (IR-) tacrolimus. We compared long-term efficacy and safety of LCPT to IR-tacrolimus applied de novo in adult OHT recipients. Methods25 prospective recipients on LCPT at our center from 2017 to 2019 were matched 1:2 with historical control recipients treated with IR-tacrolimus based on age, gender, and baseline creatinine. The primary composite outcome of death, acute cellular rejection, and/or new graft dysfunction within 3 years following transplant was compared between groups using non-inferiority analysis. ResultsLCPT demonstrated non-inferiority to IR-tacrolimus, with a primary outcome risk reduction of 16% (90%CI, −37%, −1%, non-inferiority p = 0.002) up to 3 years following heart transplant. Up to 3-years post-transplant, 14 patients remained on once-daily LCPT and 10 patients were switched to IR-tacrolimus due to lack of insurance coverage. There were no significant differences in the rate of chronic kidney disease requiring dialysis, cytomegalovirus requiring treatment, cardiac allograft vasculopathy, and malignancy within 3 years following transplant. ConclusionLCPT is non-inferior in efficacy to IR-tacrolimus in heart transplantation with a similar safety profile. Narrowly-constrained FDA labels specific to kidney transplant remain a barrier to consistent access to many immunosuppressant medications for recipients of non-kidney solid organs. We recommend the FDA consider developing facile pathways for expanding the approved label of extended-release tacrolimus formulations to heart transplant recipients.

CSF1R inhibition promotes neuroinflammation and behavioral deficits during graft-versus-host disease in mice

AbstractChronic graft-versus-host disease (cGVHD) remains a significant complication of allogeneic hematopoietic stem cell transplantation. Central nervous system (CNS) involvement is becoming increasingly recognized, in which brain-infiltrating donor major histocompatibility complex (MHC) class II+ bone marrow–derived macrophages (BMDM) drive pathology. BMDM are also mediators of cutaneous and pulmonary cGVHD, and clinical trials assessing the efficacy of antibody blockade of colony-stimulating factor 1 receptor (CSF1R) to deplete macrophages are promising. We hypothesized that CSF1R antibody blockade may also be a useful strategy to prevent/treat CNS cGVHD. Increased blood-brain barrier permeability during acute GVHD (aGVHD) facilitated CNS antibody access and microglia depletion by anti-CSF1R treatment. However, CSF1R blockade early after transplant unexpectedly exacerbated aGVHD neuroinflammation. In established cGVHD, vascular changes and anti-CSF1R efficacy were more limited. Anti-CSF1R–treated mice retained donor BMDM, activated microglia, CD8+ and CD4+ T cells, and local cytokine expression in the brain. These findings were recapitulated in GVHD recipients, in which CSF1R was conditionally depleted in donor CX3CR1+ BMDM. Notably, inhibition of CSF1R signaling after transplant failed to reverse GVHD-induced behavioral changes. Moreover, we observed aberrant behavior in non-GVHD control recipients administered anti-CSF1R blocking antibody and naïve mice lacking CSF1R in CX3CR1+ cells, revealing a novel role for homeostatic microglia and indicating that ongoing clinical trials of CSF1R inhibition should assess neurological adverse events in patients. In contrast, transfer of Ifngr–/– grafts could reduce MHC class II+ BMDM infiltration, resulting in improved neurocognitive function. Our findings highlight unexpected neurological immune toxicity during CSF1R blockade and provide alternative targets for the treatment of cGVHD within the CNS.

Effects of long-acting injectable progesterone supplementation at early dioestrus on pregnancy maintenance in beef and dairy recipient cattle.

We tested in the present study the hypothesis that supplementation with long-acting P4 (iP4) at different times of the initial dioestrus improves pregnancy rates in dairy and beef recipients submitted to fixed-time embryo transfer (FTET). Recipients from commercial farms had their oestrous cycle synchronized with an E2/P4-based protocol in three experiments (Exp. 1 to 3). In Exp. 1, dairy heifers (n = 76) and cows (n = 104) were randomly assigned to two experimental groups: the control group (n = 89) and the iP4D4 group (n = 91). For Exps. 2 and 3, suckled beef recipients were used. In Exp. 2, recipients were assigned to two experimental groups: Control group (n = 147) and iP4D7 group (n = 144); whereas in Exp. 3, recipients were randomly assigned to three experimental groups: Control group (n = 85), iP4-D4 group (n = 86) and iP4D7 group (n = 81). Recipients in the iP4D4 and iP4-D7 groups received an i.m. administration of 150 mg iP4, on D4 or D7 (D0 was the day of expected oestrus). On D7, all recipients were evaluated by transrectal ultrasonography and those that had a CL received a fresh or vitrified invitro-produced embryo. In Exp. 2 and 3, the CL area was also determined by ultrasonography at the time of FTET. The pregnancy diagnosis was performed at 30 days in Exp. 1, 57 days in Exp. 2, and between 40 and 72 days of pregnancy in Exp. 3. In Exp. 1, the pregnancy rate did not differ (p > .1) between the Control group (38.2% [34/89]) and iP4D4 group (49.5% [45/91]); yet, a parity effect indicated a greater (p < .05) pregnancy rate in heifers (57.9% [44/76]) than cows (30.8% [32/104]). In Exp. 2, the pregnancy rate was greater (p < .05) in the iP4D7 group (45.0% [65/144]) than in the Control group (34.0% [50/147]). Also, a greater (p = .08) pregnancy rate was observed for recipients with a small CL (≤2.75 cm2 ) that were treated with iP4 on the day of FTET than the control recipients (46.4% [32/69] vs. 32.6% [28/86]). In Exp. 3, no significant effects (p > .1) of the treatment group or CL size were detected on pregnancy rates at days 30 and 60. In conclusion, the beneficial effects of iP4 supplementation at early dioestrus on pregnancy maintenance may vary according to the experimental conditions, but its use at the time of FTET can be used as an alternative to enhance the fertility of beef recipients in challenging conditions in commercial herds.

Understanding the Functional Differences between PRC2.1 and PRC2.2 in Hematopoiesis

Epigenetic mechanisms play an important role in the determination of hematopoietic stem and progenitor cell (HSPC) fate through the modification of chromatin architecture. Polycomb repressive complex 2 (PRC2) is an indispensable epigenetic modifier that catalyzes histone 3 lysine 27 tri-methylation (H3K27me3) repressive mark through its catalytic subunit EZH2. PRC2 is divided into two independent complexes, PRC2.1 and PRC2.2, based on the specific interacting accessory proteins. PRC2.1 comprises one of the three polycomb-like proteins (PCL1/PHF1, PCL2/MTF2, or PCL3/PHF19), as well as one of the two recently identified accessory proteins, EPOP or PALI1. However, PRC2.2 contains either JARID2 or AEBP2 as co-factors. These accessory proteins aid in the recruitment of the PRC2 complexes to different sites in the genome to catalyze H3K27me3. Recent studies performed on mouse embryonic stem cells showed that PRC2.1 and PRC2.2 are involved in distinct lineage specification and commitment through their specific co-factors. However, the functional differences between PRC2.1 and PRC2.2 in HSPC differentiation and lineage commitment has not been thoroughly characterized. To compare the complete loss of PRC2 versus PRC2.2-specific loss of function in normal hematopoiesis, we generated Mx1-Cre: Jarid2fl/fl and Mx1-Cre: Ezh2fl/fl mouse strains. Two-month old Mx1-Cre(+) control, Mx1-Cre(+): Jarid2fl/fl, and Mx1-Cre(+): Ezh2fl/fl mice were injected with six doses of polyinosinic:polycytidylic acid (pIpC) to promote conditional deletion of Jarid2 and Ezh2. Two months post-pIpC injection, whole bone marrow (WBM) cells were used to perform competitive transplantation (5x10 5 CD45.2 test WBM plus 5x10 5 CD45.1 competitor WBM cells). Jarid2-KO primary recipients showed the highest CD45.2 peripheral blood (PB) engraftment (~80%), and the highest tri-lineage (myeloid 80%, B cell 70%, T cell 80%) chimerism compared to the control (myeloid 50%, B cell 45%, T cell 25%) and Ezh2-KO (myeloid 65%, B cell 5%, T cell 5%) recipients. Ezh2-KO recipients showed the lowest CD45.2 PB engraftment (~20%), and were deficient for PB lymphoid cell production. Jarid2-KO recipients showed the highest bone marrow (BM) engraftment (~ 90%), while Ezh2-KO recipients showed significant BM lymphoid engraftment (B cell 55% and T cell 40%) inverse to what was observed in the PB (B cell 5% and T cell 5%). This suggested that complete loss of PRC2 function promotes blockage in the migration of mature lymphoid cells from BM to the PB. Jarid2-KO and Ezh2-KO recipients showed significant reductions in phenotypically defined HSC cell number and frequency compared to control recipients suggesting that PRC2.2 function through its co-factor Jarid2 to maintain HSC pool. To further investigate the functional effect of both genes' loss of function at the molecular level, we performed single cell transcriptomic analysis from KSL (lineage-, c-Kit+, Sca1+, CD45.2+) cells sorted from the aforementioned recipients. Based on transcriptomic analysis, Ezh2 loss of function promoted an increase in MPP4 and precursor B cell populations in the BM of recipient mice. However, no significant changes was observed between control and Jarid2-KO clusters. Analysis showed that the Mtf2 co-factor has the highest expression level throughout the whole KSL clusters compared to other PRC2.1 and PRC2.2 accessory proteins. These results suggested that Mtf2-associated PRC2.1 is necessary to restrict MPP4 self-renewal and to repress B cell priming in HSPCs. Although no significant change was observed in the HSC cluster between Jarid2-KO and Ezh2-KO genotypes, Jarid2 and Ezh2 loss of functions showed significant differential gene expression in the HSC population when compared to each other and to the control suggesting that Jarid2-associated PRC2.2 regulates a unique molecular program in HSCs independently from PRC2.1. Combined with our functional data, these results suggested that PRC2.2 restricts HSC-specific gene expression in non-self-renewing progenitor cells through its co-factor Jarid2; while PRC2.1 restricts MPP4 fate and B cell priming through its co-factor Mtf2. Ongoing studies are aimed to delineate the distinct molecular programs regulated by PRC2.1 and PRC2.2 in HSPCs using CRISPR-Cas9 sgRNA lentiviral system targeting each of the PRC2.1 and PRC2.2 accessory proteins independently and validation in lineage-specific functional assays.

Recipient Resident Macrophage Plays a Crucial Role in Acute Graft-Versus-Host-Disease after Allogeneic Stem Cell Transplantation By Regulation of Damage-Associated Molecular Pattern Phagocytosis

Introduction Evidence shows allogeneic hematopoietic stem cell transplantation (alloHSCT) provides life-sustaining therapy for many hematologic malignancies. Unfortunately, in many cases it is complicated by acute-graft-versus-host disease (aGVHD), a life-threatening sequela. Most interstitial tissues contain populations of resident macrophages. Multiple studies have investigated the role of infiltrating macrophages in aGVHD, but little is known about the role of resident macrophage in aGVHD. To address this issue, we adopt a LysM cre/cre-Hif1a flox/flox mice (KO)as host mice with abnormal macrophage whose host resident macrophage remains unchanged early after allo-HSCT. KO mice received alloHSCT after Total body irradiation (TBI) from wild-type(WT) mice of BALB/c background. The neutrophil and circulating monocyte/macrophage were replaced by WT cells and the resident macrophage remains unchanged after this procedure. The grade of aGVHD and survival was observed. Methods Recipient mice are on the background of C57BL/6(H-2 b), and donor mice are wild-type BALB/c (H-2 d ) mice. All mice used were 8-12 week old. All animal experiment protocols were approved. LysM cre/cre (CRE) mice were taken as control recipients. Mice were exposed to TBI split into two doses separated by 4h. KO and CRE C57/BL mice received 9 Gy TBI. 18h after irradiation, mice of two groups were injected i.v with 1×10 7BM cells and 1.5×10 7 splenocytes isolated from WT BALB/c mice. aGVHD score and survival are monitored daily. Isolation of Kupffer subsets was performed as CD45 +CD11b + Ly6G -F4/80 +, which from KO and CRE mice of GVHD model were taken to do single-cell sequencing assay. Survival curves were plotted by the Kaplan-Meier method. The statistical significance between group means was determined using t-test by Graphpad prism9.5. The level of significance was set at P&amp;lt;0.05. Results The mean survival of KO mice is 18.6 days (95%CI 14.06-22.6) post alloHSCT, while the mean survival of control mice is 37.6 days (95%CI 29.7-45.6)(n=8)( P &amp;lt;0.001). Weight loss (% of baseline weight on the day of TBI) starts to differ on day 14 post-HSCT, with the KO group of 101.7 and Control group of 84.9 ( P &amp;lt;0.05). GVHD score starts to differ on day 10 post-HSCT, with the KO group of mean score 5.1 and control group 3.9 ( P &amp;lt;0.05)(n=8) (Figure1). The GVHD score remains statistically different till day 24 post-HSCT. On day 24, all KO mice die while one control mouse live up to 58 days. The liver function presented by ALT is different on day 14 post-HSCT, KO group with mean ALT 209.0 U/L is higher than Control group whose mean ALT is 64.9U/L(n=4). On day 21, Liver GVHD pathology score of the KO group is 7, compared to 5.2 of the control group(n=6)( P&amp;lt;0.05). Thus, KO mice present with a more severe aGVHD phenotype than CRE mice. Macrophage is known to have deficient phagocytosis ability when lacking Hif1-a, which is also confirmed through phagocytosis assay in our lab by FITC marked particles based on melamine resin ( P &amp;lt;0.05). We hypothesize the disability of phagocytosis of recipient resident macrophage renders more DNA debris (also known as DAMP) generated from conditioning, leading to susceptibility of aGVHD, we applied Dnase I to mice from day4 to day14 post-HSCT. The survival of KO mice after injection of Dnase I, with a mean survival of 39.9 days, is better than KO mice with vehicle injection ( P &amp;lt;0.05). After Dnase I injection, KO group, compared to 63.5 days mean survival of the control group, there is no statistical difference ( P=0.113). In order to look into more mechanisms, CD45 + cells from the liver of KO and CRE mice with GVHD model 21 days post-HSCT were isolated to do single-cell sequencing. KO mice revealed more T cell ratio than CRE mice. GO analysis revealed several abnormalities including regulation of lymphocyte activation. Conclusions We build GVHD model on LysM cre/cre-Hif1a flox/flox and LysM cre/cre mice, both adopt alloHSCT from wild-type BALB/c mice. After HSCT, both groups are replaced with wild-type neutrophils and circulating monocyte/macrophages, leaving resident macrophages different. KO mice present with exacerbated GVHD phenotype than CRE mice after alloHSCT. This difference could be mitigated by Dnase I injection. Thus, the resident macrophage of the recipient plays a crucial role in aGVHD occurrence, which is partly by regulation of DAMP phagocytosis.

The Challenge of Treating Relapsed Myeloid Leukemia in Children with Down Syndrome - a Targeted Analysis Using Patient-Derived Xenograft Models

Background. Myeloid leukemia occurs with a 150-fold increased incidence in children with Down syndrome (ML-DS) and is characterized by distinct disease mechanism and response to treatment. In the context of trisomy 21, somatic GATA1 mutations first initiate preleukemic transient abnormal myelopoiesis, a disorder of fetal liver hematopoiesis. Co-operating events, which target cohesin complex components, epigenetic modifiers or signal transducers including RAS pathway genes (Yoshida 2013, Labuhn M 2019), then drive transformation to ML-DS in 20% of infants with TAM, typically by age 4 years. Abnormal sonic hedgehog signaling was recently associated with trisomy 21 (Galati 2019). Its role in the development of ML-DS is unknown. Hypersensitivity of ML-DS blasts to chemotherapy with cytarabine and other agents accounts at least in part for the more favorable response of ML-DS compared to acute myeloid leukemia of children without DS. Contemporary treatment protocols for ML-DS achieve event-free and overall survival of approx. 89% and 90% at 5 years (Taub 2017). In marked contrast, patients who develop a relapse of ML-DS face a significantly lower probability of survival (EFS 20.9% and OS 22% at 3 years, Raghuram 2023), compared to children with relapsed AML who do not have DS, and appear to be resistant against conventional chemotherapy. Since the few survivors with a relapsed ML-DS are almost exclusively found among patients who first achieve a second remission and then undergo hematopoietic stem cell transplantation, successful identification of agents with efficacy against the blasts of relapsed ML-DS is essential for survival. We tested if blasts of relapsed ML-DS had lost their sensitivity to cytarabine and whether new drugs could be identified that target pathways active in the blasts of ML-DS. Patients, Materials and Methods . We used patient-derived xenografts (PDX) of human ML-DS and relapsed ML-DS blasts in immunodeficient mice (NSG and NSG-W41) to determine in vivo responses to standard chemotherapeutic agents (cytarabine, vincristine) and novel approaches such as demethylating agents (azacytidine), inhibition of histone deacetylation (panobinostat), mTOR (rapamycin), PARP (olaparib), and sonic hedgehog signaling (glasdegib) alone or in combination (glasdegib + cytarabine; panobinostast + azacytidine). Injection of leukemic cells was performed intrafemorally. Endpoint was inhibition of leukemic engraftment compared to control recipients receiving vehicle only. Results.Responses of primary and relapsed ML-DS samples to drugs tested in PDX models showed marked heterogeneity. While some ML-DS samples showed resistance to cytarabine at the time of relapse this was not the universal cause of failure of primary treatment of ML-DS and some blasts of relapsed ML-DS retained sensitivity to cytarabine. Some primary and relapsed ML-DS blasts showed unexpected sensitivity to vincristine, a drug more commonly used to treat acute lymphoblastic leukemia. Despite intriguing rationales we observed no responses of primary and relapsed ML-DS blasts to the PARP inhibitor olaparib, mTOR inhibition by rapamycin and sonic hedgehog inhibition by glasdegib. Conclusions. Loss of hypersensitivity to cytarabine was not universal at the time of ML-DS relapse. Some agents not typically used to treat AML, such as vincristine, showed unexpected efficacy whereas others lacked responses despite a plausible mechanistic rationale. Patient-specific molecular mechanisms underlying relapsed ML-DS are likely to have an impact on drug sensitivity. They should be determined for all patients with relapsed ML-DS to assist identification of targets and selection of drugs in order to establish urgently needed but currently still lacking efficacious treatment for relapsed ML-DS.

Soluble Urokinase-Type Plasminogen Activator Receptor (suPAR) and Growth Differentiation Factor-15 (GDF-15) Leves Are Significantly Associated with Edothelial Injury Indices in Adult Allogenic Hematopoietic Cell Transplantation Recipients

Introduction: Endothelial dysfunction is a common denominator of graft-versus-host disease (GVHD) and transplant-associated thrombotic microangiopathy (TA-TMA). Among endothelial injury indices, the Endothelial Activation and Stress Index (EASIX) has been studied in allogeneic hematopoietic cell transplantation recipients (allo-HCT) recipients, while others including suPAR and GDF-15 have been determined only in other patient populations with hematologic diseases, such as in patients with Multiple Myeloma, AL- amyloidosis and Sickle Cell Disease. We hypothesized that suPAR and GDF-15 would reflect endothelial injury in allo-HCT recipients. Methods: We enrolled consecutive adult TA-TMA (classified according to current standardized criteria), acute and/or chronic graft-versus-host-disease (GVHD), control allogeneic hematopoietic cell transplantation (alloHCT) recipients and apparently healthy individuals of similar age and gender in a 1:1:1:1 ratio. Plasma was collected and stored immediately at -80 oC at the first day of confirmed TA-TMA or GVHD diagnosis and at a similar post-transplant period in control recipients. EASIX [lactate dehydrogenase (U/L) × creatinine (mg/dL)/thrombocytes (10⁹ cells per L)] was calculated at day 0, 30, 100 and at last follow-up. Soluble C5b-9/membrane attack complex, suPAR and GDF-15 levels were measured using immunoenzymatic techniques. Results: We studied 20 TA-TMA, 20 GVHD, 20 control alloHCT patients, and 20 healthy controls. We found significantly higher suPAR and GDF-15 levels in TA-TMA and GVHD patients compared to alloHCT and healthy controls (p&amp;lt;0.001, Bonferroni's correction). Then, we further analyzed characteristics of the alloHCT population. TA-TMA developed at a median of 125 post-transplant day (range 9-2931); whereas the first day of confirmed GVHD diagnosis was at a median of 78 post-transplant day (range 16-145). Both GDF-15 and suPAR concentrations were associated with EASIX at day 100 (r=0.351, p=0.012 and r=0.338, p=0.015, respectively) and last follow-up (r=0.473, p&amp;lt;0.001 and r=0.410, p=0.020, respectively). Among the laboratory values used to calculate EASIX (LDH, creatinine, platelets), suPAR was associated with creatinine and platelets at day 100 and last follow-up; while GDF-15 only with platelets at both time points, suggesting that the association with EASIX is not driven by laboratory values per se. Interestingly, only suPAR and not GDF-15 levels was associated with soluble C5b-9 levels (p=0.013), a marker reflecting high risk in TA-TMA. Conclusion: Our study shows for the first time that suPAR and GDF-15 reflect endothelial injury in allo-HCT recipients. In accordance with other patient populations, suPAR emerges as a marker of renal dysfunction, characterizing high-risk in endothelial injury syndromes and in particular, TA-TMA. However, prior to their clinical usefulness, these biomarkers must undergo through rigorous validation in multiple cohorts.

Vaccination of cattle with the Babesia bovis sexual-stage protein HAP2 abrogates parasite transmission by Rhipicephalus microplus ticks

The apicomplexan parasite Babesia bovis is responsible for bovine babesiosis, a poorly controlled tick-borne disease of global impact. The widely conserved gametocyte protein HAPLESS2/GCS1 (HAP2) is uniquely expressed on the surface of B. bovis sexual stage parasites and is a candidate for transmission-blocking vaccines (TBV). Here, we tested whether vaccination of calves with recombinant HAP2 (rHAP2) interferes with the transmission of B. bovis by competent ticks. Calves vaccinated with rHAP2 (n = 3), but not control animals (n = 3) developed antibodies specific to the vaccine antigen. Vaccinated and control animals were infested with Rhipicephalus microplus larvae and subsequently infected with virulent blood stage B. bovis parasites by needle inoculation, with all animals developing clinical signs of acute babesiosis. Engorged female ticks fed on the infected calves were collected for oviposition, hatching, and obtention of larvae. Transmission feeding was then conducted using pools of larvae derived from ticks fed on rHAP2-vaccinated or control calves. Recipient calves (n = 3) exposed to larvae derived from control animals, but none of the recipient calves (n = 3) challenged with larvae from ticks fed on rHAP2-vaccinated animals, developed signs of acute babesiosis within 11 days after tick infestation. Antibodies against B. bovis antigens and parasite DNA were found in all control recipient animals, but not in any of the calves exposed to larvae derived from HAP2-vaccinated animals, consistent with the absence of B. bovis infection via tick transmission. Overall, our results are consistent with the abrogation of parasite tick transmission in rHAP2-vaccinated calves, confirming this antigen as a prime TBV candidate against B. bovis.

Durable Anti-Vi IgG and IgA Antibody Responses in 15-Month-Old Children Vaccinated With Typhoid Conjugate Vaccine in Burkina Faso.

We assessed anti-Vi IgG/IgA responses to typhoid conjugate vaccine (TCV) in children enrolled in a double-blind randomized controlled, phase 2 trial in Burkina Faso. Anti-Vi IgG seroconversion and anti-Vi IgA titers were higher in TCV than control recipients at 30-35 months post-vaccination. TCV induces durable immunity in Burkinabe children vaccinated at 15 months.

Glucocorticoids redirect naive T cells to the bone marrow in malnourished mice

Abstract Glucocorticoids contribute to the daily migration patterns of T cells in well-nourished organisms and are elevated in the malnourished. We examined the effect of malnutrition on T cell migration by comparing the migration patterns of adoptively transferred malnourished and control T cells in the lymphoid organs of malnourished and control recipients. We found that malnourished T cells generally entered lymphoid tissues more efficiently than control T cells, regardless of recipient. Strikingly, the bone marrow of malnourished recipients attracted naïve malnourished T cells, but not control T cells, more efficiently than control bone marrow. In contrast, the spleens of malnourished and control mice attracted similar numbers of naïve T cells. Further experiments revealed that T cells residing in the bone marrow of malnourished mice express higher levels of CCR7 and lower levels of CD11a than control T cells. We also examined the effect of T cell-specific deficiency of the glucocorticoid receptor on T cell migration to the bone marrow in malnourished mice. Indeed, similarly low percentages of glucocorticoid receptor deficient T cells were observed in the bone marrow of malnourished and control mice, indicating that T cell expression of the glucocorticoid receptor is required for T cell migration to the bone marrow. Overall, we have determined that malnutrition modifies both the bone marrow and naïve T cells to promote naïve T cell migration to the bone marrow and that at least the T cell-specific effects are mediated via the glucocorticoid receptor. NSF-MRI [DBI- 1920116] NSF-RUI [IOS-1951881]

Intermediate levels of preexisting protective antibody allow priming of protective T cell immunity against Influenza

Abstract Overcoming interfering impacts of preexisting immunity to generate universally protective influenza A virus (IAV)-specific T cell immunity through vaccination is a high priority. Here, we passively transfer varied amounts of H1N1-IAV-specific immune serum prior to H1N1-IAV infection to determine how different levels of preexisting Ab influence the generation and protective potential of heterosubtypic T cell responses in a murine model. Surprisingly, IAV nucleoprotein (NP)-specific CD4 and CD8 T cell responses are readily detected in infected recipients of IAV-specific immune serum regardless of the amount transferred. When compared to responses in control groups and recipients of low and intermediate levels of convalescent serum, NP-specific T cell responses in recipients of high levels of IAV-specific serum, which prevent overt weight loss and reduce peak viral titers in the lungs, are, however, markedly reduced. While detectable at priming, this response recalls poorly and is unable to mediate protection against a lethal heterotypic (H3N2) virus challenge at later memory timepoints. A similar failure to generate protective heterosubtypic T cell immunity during IAV priming is seen in offspring of IAV-primed mothers that naturally receive high titers of IAV-specific Ab through maternal transfer. Our findings support that priming of protective heterosubtypic T cell responses can occur in the presence of intermediate levels of preexisting Ab. These results have high relevance to vaccine approaches aiming to incorporate and evaluate cellular and humoral immunity against IAV and other viral pathogens against which T cells can protect against variants escaping Ab-mediated protection. Supported grants from NIH (RO1 AI165406) Startup funds from the University of Central Florida foundation

Intermediate Levels of Pre-Existing Protective Antibody Allow Priming of Protective T Cell Immunity against Influenza.

Overcoming interfering impacts of pre-existing immunity to generate universally protective influenza A virus (IAV)-specific T cell immunity through vaccination is a high priority. In this study, we passively transfer varied amounts of H1N1-IAV-specific immune serum before H1N1-IAV infection to determine how different levels of pre-existing Ab influence the generation and protective potential of heterosubtypic T cell responses in a murine model. Surprisingly, IAV nucleoprotein-specific CD4 and CD8 T cell responses are readily detected in infected recipients of IAV-specific immune serum regardless of the amount transferred. When compared with responses in control groups and recipients of low and intermediate levels of convalescent serum, nucleoprotein-specific T cell responses in recipients of high levels of IAV-specific serum, which prevent overt weight loss and reduce peak viral titers in the lungs, are, however, markedly reduced. Although detectable at priming, this response recalls poorly and is unable to mediate protection against a lethal heterotypic (H3N2) virus challenge at later memory time points. A similar failure to generate protective heterosubtypic T cell immunity during IAV priming is seen in offspring of IAV-primed mothers that naturally receive high titers of IAV-specific Ab through maternal transfer. Our findings support that priming of protective heterosubtypic T cell responses can occur in the presence of intermediate levels of pre-existing Ab. These results have high relevance to vaccine approaches aiming to incorporate and evaluate cellular and humoral immunity towards IAV and other viral pathogens against which T cells can protect against variants escaping Ab-mediated protection.

Abstract B036: Platelets promote in vitro osteosarcoma cell migration and in vivo metastatic lung seeding

Abstract Osteosarcoma (OS) is the most common primary bone cancer worldwide where it mainly affects adolescents. Metastatic OS has a 20% survival rate and treatment options remain poor, thus understanding mechanisms that contribute to OS metastasis is critical for improved patient outcomes. Platelets, commonly recognized for their role in hemostasis, have been shown to promote metastasis in several cancer models. However, most previous studies investigating platelet contributions to metastasis have focused on carcinomas while their role in osteosarcoma remains poorly understood. Previous studies by our lab have shown that platelet interactions with breast cancer cells resulted in increased migration in vitro and increased lung metastases in vivo. Thus, we hypothesized that OS cell migration will be enhanced in the presence of platelets, and that platelet depletion in vivo will inhibit OS lung seeding. Cell suspensions of SaOs2 and MG63.3 cells in serum free media were fluorescently stained and seeded, in triplicates, in the top chamber of an 8um pore Fluoroblock migration assay wells. In the bottom chamber, media and either Tyrode’s buffer or 1.5x106 isolated human platelets were added. The presence of platelets resulted in a 3.5- and 4.6-fold increase of migrated MG63.3 and SaOs2 cells respectively. For in vivo analysis, cohorts of eight-week-old, male Nod Scid-Gamma (NSG), Nod Scid, and Nude mice were randomly assigned to either the control or platelet depletion group. Mice were depleted of platelets by administration of Anti-Platelet glycoprotein Ib alpha (GPIbα) antibody and, 5x105 GFP transduced MG63.3 cells were injected via tail vein. 24 hrs later, the mice were euthanized, and lungs were collected and microscopically imaged. Platelet depletion in NSG mice resulted in a 48% reduction in MG63.3 lung seeding compared to the isotype control recipient mice. This result was more dramatic in the less immunocompromised Nude and Nod Scid mice with a 61% and 87% reduction of MG63.3 lung seeding in the platelet depleted mice respectively. Finally, RNAseq and was performed on seven OS cell lines co-cultured with isolated mouse platelets, and alterations in gene expression were compared to control cells. Gene Enrichment Set Analysis (GSEA) of the data indicated that platelet co-incubation significantly upregulated pathways related to inflammatory responses, Tumor Necrosis Factor (TNF)-a signaling, and Interleukin (IL)-6 signaling. These results suggest that platelet secreted factors facilitate OS cell migration in vitro while an immune dependent mechanism is involved in the role of platelets in the in vivo lung seeding of OS cells. Citation Format: Olivia K. Travis, Ruishan Wang, Myriam Labelle. Platelets promote in vitro osteosarcoma cell migration and in vivo metastatic lung seeding [abstract]. In: Proceedings of the AACR Special Conference: Cancer Metastasis; 2022 Nov 14-17; Portland, OR. Philadelphia (PA): AACR; Cancer Res 2022;83(2 Suppl_2):Abstract nr B036.