IL-10 In Response Research Articles

P-1863. Maternal Mycobacterial-Specific T-cell Signatures and Infant Risk of Mycobacterium tuberculosis Infection

Abstract Background Tuberculosis disease (TB) caused 214,000 pediatric deaths in 2022. A growing body of evidence suggests that HIV exposed uninfected infants (iHEU) are at increased risk for Mycobacterium tuberculosis (Mtb) infection. Harnessing the power of the maternal immune system to protect infants has shown promise in other infections. Yet no well powered study has evaluated the association between maternal mycobacterial-specific T cell memory and infant protection from Mtb infection. To address this knowledge gap, we examined the hypothesis that previously undescribed maternal factors modulate infant immunity to bacillus Calmette-Guèrin (BCG) and Mtb.Fig 1.Mothers of infants negative for Mtb infection had higher proportions of CD8 T cells expressing IL2 in response to mycobacterial antigens.ESAT-6/CFP-10 negative median 0.004710 (95% CI 0.00096000-0.01103), positive median 0.0 (95% CI 0-0.009410). TBWCL negative median 0.01172 (95% CI 0.005340-0.01860), positive median 0.003710 (95% CI 0-0.008467). Methods This study was nested within a randomized controlled trial of isoniazid to prevent Mtb infection in 300 iHEU (iTIPS) who were vaccinated with BCG at birth, randomized to isoniazid or placebo at 6-10 weeks, and had Quantiferon-Plus (with IFNγ, IL2, IP10, TNF measured in supernatant) (QFT-4) at 14 months, and/or tuberculin skin testing (TST) at 14 and 24 months. Paired maternal peripheral blood mononuclear cells were collected at the 6-10 week visit. The majority (73%) of mothers started antiretroviral therapy before pregnancy, 26.3% during pregnancy, and 0.7% after pregnancy. Frequency of self-reported history of TB disease was 10.7%. We assessed the response of maternal T cells to Mtb whole cell lysate (TBWCL), a proxy for BCG, and ESAT-6/CFP-10 (E6C10), an Mtb specific peptide pool, by flow cytometry with a T cell panel including surface, memory, and activation markers and IL2, IL17A, IFNγ, and TNF. Results Our preliminary analysis of 166 of 235 maternal samples with flow cytometry revealed that mothers of infants with positive TST or QFT-4 had significantly fewer CD8+IL2+ cells in response to TBWCL (median 0.0037% vs 0.0117%, p=0.032) (Fig 1). Conversely mothers of these infants had significantly higher CD4+TNFa+ responses to E6C10 (median 0.0458% vs 0%, p=0.0014) and CD4+IFNγ+ responses to TBWCL (median 0.0533% vs 0.0302%, p=0.0395). Conclusion These results establish that maternal mycobacterial-specific immune signatures are associated with infant outcomes, which we plan to further investigate by comparing these maternal signatures with infant T cell response to TBWCL and determining the role of maternal microchimeric cells. Disclosures Sylvia M. LaCourse, MD, MPH, Merck: Grant/Research Support|UpToDate: Royalties

Mitochondria complex III-generated superoxide is essential for IL-10 secretion in macrophages.

Mitochondrial electron transport chain (ETC) function modulates macrophage biology; however, mechanisms underlying mitochondria ETC control of macrophage immune responses are not fully understood. Here, we report that mutant mice with mitochondria ETC complex III (CIII)-deficient macrophages exhibit increased susceptibility to influenza A virus (IAV) and LPS-induced endotoxic shock. Cultured bone marrow-derived macrophages (BMDMs) isolated from these mitochondria CIII-deficient mice released less IL-10 than controls following TLR3 or TLR4 stimulation. Unexpectedly, restoring mitochondrial respiration without generating superoxide using alternative oxidase (AOX) was not sufficient to reverse LPS-induced endotoxic shock susceptibility or restore IL-10 release. However, activation of protein kinase A (PKA) rescued IL-10 release in mitochondria CIII-deficient BMDMs following LPS stimulation. In addition, mitochondria CIII deficiency did not affect BMDM responses to interleukin-4 (IL-4) stimulation. Thus, our results highlight the essential role of mitochondria CIII-generated superoxide in the release of anti-inflammatory IL-10 in response to TLR stimulation.

IFN-γ/TNF-α Synergism Induces Pro-Inflammatory Cytokine and Chemokine Production by In Vitro Canine Keratinocytes.

Activated keratinocytes play a crucial role in skin inflammation through the production of multiple inflammatory mediators; however, little is known about cytokine secretion by activated keratinocytes in dogs. This study aimed to investigate the effects of the Th1 and Th2 types of cytokines on the production of keratinocyte-derived inflammatory mediators. Canine progenitor epidermal keratinocytes (CPEKs) were incubated with canine recombinant IL-4, IL-13, an IL4/IL13 mixture, IFN-γ, TNF-α, or an IFN-γ/TNF-α mixture for 24 h following 100% confluency. Culture supernatants were analyzed for cytokine concentration, including chemokine ligand (CXCL) 8, IL-10, IL-6, IL-1ß, IL-12, and chemokine ligand 2 (CCL2) by enzyme-linked immunosorbent assay. CPEKs incubated with the IFN-γ/TNF-α mixture showed significantly increased IL-6 concentration. In addition, significantly increased concentrations of CXCL8 were detected in CPEKs incubated with TNF-α and with the IFN-γ/TNF-α mixture. CCL2 concentrations increased in cells incubated with IFN-γ, TNF-α, and the IFN-γ/TNF-α mixture. The IFN-γ/TNF-α mixture synergistically enhanced CCL2 production. Dose-dependent elevations were also observed in IL-6 in response to the IFN-γ/TNF-α mixture, and in CCL2 in response to IFN-γ, TNF-α, and the IFN-γ/TNF-α mixture. These findings indicate that IFN-γ and TNF-α synergistically increase pro-inflammatory cytokines and chemokines secreted by canine keratinocytes. This in vitro culture system could be useful to investigate cytokine-mediated crosstalk between keratinocytes and immune cells and new therapeutic strategies for keratinocyte-mediated inflammatory skin diseases.

Impact of SARS-CoV-2 vaccination and of seasonal variations on the innate immune inflammatory response.

The innate immune response is an important first checkpoint in the evolution of an infection. Although adaptive immunity is generally considered the immune component that retains antigenic memory, innate immune responses can also be affected by previous stimulations. This study evaluated the impact of vaccination on innate cell activation by TLR7/8 agonist R848, as well as seasonal variations. To this end, blood samples from a cohort of 304 food and retail workers from the Quebec City region were collected during three visits at 12-week intervals. Peripheral blood mononuclear cells and polymorphonuclear neutrophils were isolated during the first and third visits and were stimulated with R848 to assess the innate immune response. Our results show that IL-8 production after stimulation decreased after vaccination. In addition, the IL-8 response was significantly different depending on the season when the visit occurred, for both COVID-19 vaccinated and unvaccinated individuals. This study highlights that innate immune responses can be affected by SARS-CoV-2 vaccination and fluctuate seasonally.

Influence of Biological Sex and Congenital Iron Deficiency on Neonatal Cytokine Responses.

Stimulated cord blood mononuclear cell (CBMC) cytokine responses were previously shown to predict the risk of childhood atopic disease. Iron deficiency (ID) at birth may also program atopic disease. Males are at a higher risk of pediatric atopic disease, but it is not known whether congenital ID impacts CBMC immune responses differentially by sex. Cord blood (CB) samples were collected from healthy term or near-term neonates after elective cesarean deliveries. A transferrin saturation ≤ 25% defined congenital ID. CBMCs were stimulated with either phytohemagglutinin (PHA) or PHA plus an iron chelator. Of the 85 neonates, the 26 neonates with congenital ID exhibited lower plasma tumor necrosis factor-α (TNF-α), as well as higher CBMC TNF-α and IL-8 responses than iron-sufficient neonates (p = 0.017, p = 0.013, and p = 0.007, respectively). Higher CBMC TNF-α responses were seen in both males and females with congenital ID. However, females with congenital ID also had lower plasma IL-6, lower plasma TNF-α, and higher CBMC interleukin (IL)-8 responses. Additionally, iron chelation during culture influenced stimulated CBMC IFN-γ and CBMC TNF-α responses. Congenital ID may influence stimulated CBMC cytokine responses, but results point to a sex-specific regulation of immune balance at birth. Because males are more prone to infantile ID and more likely to develop early childhood asthma, future studies should further investigate how fetal sex and congenital iron status impacts childhood immune responsiveness to infections and antigenic stimulation from the rearing environment.

The Role of Regulatory B Lymphocytes in Allergic Diseases.

Regulatory B cells (Bregs) are a key component in the regulation of the immune system. Their immunosuppressive function, which includes limiting the inflammatory cascade, occurs through interactions with other immune cells and the secretion of cytokines, primarily IL-10. As knowledge about B cells continues to expand, their diversity is becoming more recognized, with many subpopulations identified in both human and animal models. However, identifying specific transcription factors or markers that could definitively distinguish regulatory B cells remains a challenge. This review summarizes recent findings on the role of B regulatory cells in allergic diseases. In patients with bronchial asthma, atopic dermatitis, and food allergies, the number of regulatory B cells is reduced, and disease severity is inversely proportional to the quantity of these cells. Furthermore, in patients with atopic dermatitis, the ability of regulatory B cells to produce IL-10 in response to IL-6 stimulation is diminished. However, allergen immunotherapy has been shown to induce the formation of regulatory T cells as well as regulatory B cells. The success of future therapies based on B cells may depend on deepening our current understanding of their phenotypes, induction, differentiation, and function. Research in these areas is essential for understanding the mechanisms regulating Breg activity and for developing potential targeted therapies in the treatment of allergic diseases.

Functional characterization of human IL-8 in vascular stenosis using a novel humanized transgenic mouse model

IL-8 (aka interleukin 8, CXCL8) is a prototypic cytokine that is highly expressed in the diseased vessel wall and its plasma concentration is strongly associated with cardiovascular events. However, whether IL-8 plays a causative role in cardiovascular diseases remains largely unknown. In this study we used a human IL-8 transgenic (Tg) mouse strain with a bacterial artificial chromosome (BAC) integrated into its genome. This BAC encompasses 166 kb of sequence encompassing the human IL-8 gene locus as well as upstream and downstream DNA sequences containing regulatory elements. This BAC ensured a pathophysiologically regulated, rather than forced constitutive, expression of human IL-8 in the mouse. Tg mice were subjected to complete carotid ligation injury. IL-8 was highly expressed in the ligation-injured carotid artery from 3 days until 2 weeks after injury. As a result, exacerbated neointimal hyperplasia and increased Mac2 and PCNA positive cells were observed in Tg mice. To further confirm its role in promoting neointimal formation, IL-8 was neutralized by anti-IL8 treatment at the ligation site. Consequently, the size of neointima was significantly reduced. Our results provided new insights into the regulation and function of IL-8 in response to vascular insult and during neointima formation.

Characterization of Regulatory B Cells and IL-10 in Response to Ischemic Reperfusion and Potential for Infusion Therapy

Characterization of Regulatory B Cells and IL-10 in Response to Ischemic Reperfusion and Potential for Infusion Therapy

Tipping-point transition from transient to persistent inflammation in pancreatic islets

Type 2 diabetes (T2D) is associated with a systemic increase in the pro-inflammatory cytokine IL-1β. While transient exposure to low IL-1β concentrations improves insulin secretion and β-cell proliferation in pancreatic islets, prolonged exposure leads to impaired insulin secretion and collective β-cell death. IL-1 is secreted locally by islet-resident macrophages and β-cells; however, it is unknown if and how the two opposing modes may emerge at single islet level. We investigated the duality of IL-1β with a quantitative in silico model of the IL-1 regulatory network in pancreatic islets. We find that the network can produce either transient or persistent IL-1 responses when induced by pro-inflammatory and metabolic cues. This suggests that the duality of IL-1 may be regulated at the single islet level. We use two core feedbacks in the IL-1 regulation to explain both modes: First, a fast positive feedback in which IL-1 induces its own production through the IL-1R/IKK/NF-κB pathway. Second, a slow negative feedback where NF-κB upregulates inhibitors acting at different levels along the IL-1R/IKK/NF-κB pathway—IL-1 receptor antagonist and A20, among others. A transient response ensues when the two feedbacks are balanced. When the positive feedback dominates over the negative, islets transit into the persistent inflammation mode. Consistent with several observations, where the size of islets was implicated in its inflammatory state, we find that large islets and islets with high density of IL-1β amplifying cells are more prone to transit into persistent IL-1β mode. Our results are likely not limited to IL-1β but are general for the combined effect of multiple pro-inflammatory cytokines and chemokines. Generalizing complex regulations in terms of two feedback mechanisms of opposing nature and acting on different time scales provides a number of testable predictions. Taking islet architecture and cellular heterogeneity into consideration, further dynamic monitoring and experimental validation in actual islet samples will be crucial to verify the model predictions and enhance its utility in clinical applications.

Increase in serum IL-4 in response to venetoclax therapy in xenograft models of acute myeloid leukaemia

Increase in serum IL-4 in response to venetoclax therapy in xenograft models of acute myeloid leukaemia

Absence of c-Maf and IL-10 enables Type I IFN enhancement of innate responses to low-dose LPS in alveolar macrophages.

Alveolar macrophages (AMs) are lower-airway resident myeloid cells and are among the first to respond to inhaled pathogens. Here, we interrogate AM innate sensing to Pathogen Associated Molecular Patterns (PAMPs) and determine AMs have decreased responses to low-dose LPS compared to other macrophages, as measured by TNF, IL-6, Ifnb, and Ifit3. We find the reduced response to low-dose LPS correlates with minimal TLR4 and CD14 surface expression, despite sufficient internal expression of TLR4. Additionally, we find that AMs do not produce IL-10 in response to a variety of PAMPs due to low expression of transcription factor c-Maf and that lack of IL-10 production contributes to an enhancement of pro-inflammatory responses by Type I IFN. Our findings demonstrate that AMs have cell-intrinsic dampened responses to LPS, which is enhanced by type I IFN exposure. These data implicate conditions where AMs may have reduced or enhanced sentinel responses to bacterial infections.

Antiphospholipid-exposed trophoblast-derived extracellular vesicles express elevated levels of TLR7/8-activating microRNAs and induce endometrial endothelial activation, in part, through TLR7

Women with antiphospholipid syndrome (APS) are at high risk for miscarriage and preeclampsia. Unlike pro-thrombotic systemic APS, obstetric APS is associated with insufficient placentation, as well as inflammation and vascular dysfunction at the maternal-fetal interface. Antiphospholipid antibodies (aPL) can target the placental trophoblast and induce inflammation. We reported that aPL trigger trophoblast cells to produce elevated levels of IL-8 through activation of Toll-like receptor 4 (TLR4). Downstream of TLR4, we found this IL-8 response is mediated by a TLR8-activating microRNA (miR), miR-146a-3p, which is also released by the trophoblast via extracellular vesicles (EVs). Since endothelial dysfunction is a feature of obstetric APS, we sought to determine if other miRs that can activate the RNA sensors, TLR7 and/or TLR8, are released by the trophoblast via EVs after exposure to aPL, and if these EVs can activate human endometrial endothelial cells (HEECs). Using a human first trimester extravillous trophoblast cell line we found that aPL elevated their release of small EVs (<150 nm). These extracellular vesicles released from trophoblast cells exposed to aPL expressed elevated levels of TLR7/8-activating miR-21a and miR-29a, in addition to the previously reported miR-146a-3p. Extracellular vesicles from aPL-exposed human trophoblast cells triggered human endometrial endothelial cells to generate an inflammatory IL-8 response, in part through TLR7. This study highlights EVs as a mode of communication between the placenta and the maternal vasculature, as well as a potential role for TLR7/8-activating miRs in contributing to inflammation at the maternal-fetal interface in obstetric APS.

Group2 innate lymphoid cells ameliorate renal fibrosis and dysfunction associated with adenine-induced CKD

Renal fibrosis is a common pathway of chronic kidney disease (CKD) progression involving primary kidney injury and kidney diseases. Group 2 innate lymphoid cells (ILC2s) mediate type 2 immune responses irrespective of antigen presentation and play a reno-protective role in kidney injury and disease. In the present study, we observed a decrease in kidney-resident ILC2s in CKD and found that enrichment of ILC2s in the kidney ameliorates renal fibrosis. In CKD kidney, ILC2s preferentially produced IL-13 over IL-5 in response to IL-33 stimulation, regardless of ST2L expression. Moreover, GATA3 expression was decreased in ILC2s, and T-bet+ ILC1s and RORγt+ ILC3s were increased in CKD kidney. Adoptive transfer of kidney ILC2s into adenine-induced CKD model mouse improved renal function and fibrosis. Renal fibroblasts cultured with IL33-activated kidney ILC2s suppressed myofibroblast trans-differentiation through Acta2 and Fn-1 regulation. These results suggest that kidney ILC2s prevent CKD progression via improvement of renal fibrosis. Our findings also suggest that ILC2s may contribute to the development of new therapeutic agents and strategies for tissue fibroses.

Abstract PO2-17-12: Phase I Trial of alpha-lactalbumin vaccine in high risk operable triple negative breast cancer (TNBC) and patients at high genetic risk for TNBC

Abstract Background: Triple-negative breast cancer (TNBC) has a poor prognosis and may be associated with germline mutations. α-Lactalbumin (aLA) is expressed in lactating breasts but not at other times or in other tissues. Expression of aLA is found in 70% of TNBC (PMID: 27322324) so could be an immunologic target for TNBC based on the “retired protein hypothesis” (PMID: 31926646). In pre-clinical studies, vaccination with aLA provided protection from development of autochthonous tumors in transgenic murine models of breast cancer and inhibited growth of established 4T1 transplantable breast tumors in BALB/c mice (PMID: 20512124). Methods: To determine the safety and immunogenicity of aLA, patients with early stage TNBC are being entered in a Phase I trial of aLA with GMP-grade zymosan adjuvant in Montanide ISA 51 VG vehicle. Subjects receive 3 vaccinations given once every 2 weeks. Events of Common Terminology Criteria for Adverse Events (CTCAE) grade ≥ 2 are considered dose-limiting toxicities (DLTs). Results: CTCAE toxicity by dose level is summarized below. All DLTs were injection site reactions, with ulceration and need for incisional drainage representing the grade 3 events. Seven (7) of 10 patients assayed to date have met protocol specified definitions of an immune response based on ELISpot assays to determine frequencies of T cells producing IFNγ and IL-17 in response to recombinant aLA. Assays for an additional 6 patients will be available in September 2023. Conclusion: Dose level ≤ 2 appears to be the maximum tolerated dose. Based on immune response, additional intermediate dose levels may be studied. An additional cohort of patients receiving concurrent anti-PD1 treatment is being accrued. Accrual of patients with BRCA1/2 or PALB2 mutations planning to undergo prophylactic mastectomy is beginning in order to define the toxicity and immunologic effects in this group and to determine whether inflammatory changes from occult lactational foci will be produced. Funding Source: Department of Defense (W81XWH-17-1-0592 and W81XWH-17-1-0593) Table 1 Worst Toxicity by Dose Level Citation Format: Justin Johnson, Emily Rhoades, Holly Levengood, Halle Moore, Megan Kruse, Erin Roesch, Jame Abraham, Brenna Elliott, Rachel Swartz, Holly Pederson, Elena Haury, Azka Ali, Tiffany Onger, Andrew Sciallis, Zahraa Al-Hilli, Wei Wei, Thaddeus Stappenbeck, George Budd. Phase I Trial of alpha-lactalbumin vaccine in high risk operable triple negative breast cancer (TNBC) and patients at high genetic risk for TNBC [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO2-17-12.

Immune profiling reveals umbilical cord blood mononuclear cells from South India display an IL-8 dominant, CXCL-10 deficient polyfunctional monocyte response to pathogen-associated molecular patterns that is distinct from adult blood cells.

Neonate responses to pathogen-associated molecular patterns (PAMPS) differ from adults; such understanding is poor in Indian neonates, despite recognized significant infectious risk. Immune profiling analysis was undertaken of 10 secreted mediators contextualized with cellular source induced by six PAMPs in umbilical cord (CB; n = 21) and adult-blood (PBMC; n = 14) from a tertiary care hospital in South India. Differential cytokine expression analysis (minimum log2-fold difference; adj P-value < 0.05) identified bacterial PAMPs induced higher concentrations of IL-1β, IL-10, TNF-α in adults versus IL-8, GM-CSF, IFN-γ, and IL-2 in CB. CB responded to poly I:C and SARS-CoV-2 lysate with a dominant IL-8 response, whereas in PBMC, CXCL-10 dominated poly I:C, but not SARS-CoV-2, responses, highlighting potential IL-8 importance, in the absence of Type I Interferons, in antiviral CB immunity. Candida albicans was the only PAMP to uniformly induce higher secretion of effectors in CB. The predominant source of IL-8/IL-6/TNF-α/IL-1β in both CB and PBMC was polyfunctional monocytes and IFN-γ/IL-2/IL-17 from innate lymphocytes. Correlation matrix analyses revealed IL-8 to be the most differentially regulated, correlating positively in CB versus negatively in PBMC with IL-6, GM-CSF, IFN-γ, IL-2, consistent with more negatively regulated cytokine modules in adults, potentially linked to higher anti-inflammatory IL-10. Cord and adult blood from India respond robustly to PAMPs with unique effector combinations. These data provide a strong foundation to monitor, explore, mechanisms that regulate such immunity during the life course, an area of significant global health importance given infection-related infant mortality incidence.

Enteric pathogen targeting of the inflammasome pathway

Abstract Pattern recognition receptors-based sensing of microbial products and activities to mount an effective antibacterial defense is an evolutionarily conserved immune strategy. Cytosolic LPS sensing by caspase-11 or -4 and the ensuing noncanonical inflammasome-mediated IL-1 and cell death responses play a central role in the clearance of bacterial pathogens. In response to this selection pressure from the host it is natural that pathogens have developed strategies to actively antagonize or evade inflammasome responses. However, the mechanisms by which bacterial pathogens subvert the noncanonical inflammasome pathway is only beginning to be understood. In this context, this study investigates bacterial modulation of noncanonical inflammasome by utilizing Salmonella entericaserovar Typhimurium as a model enteric pathogen. By screening a library of defined single gene mutants of S. Typhimurium, we found that a mutant that lacks a Salmonella Pathogenicity Island 1 (SPI-1) effector triggers a markedly higher cell death and IL-1 responses in epithelial and professional innate immune cells indicating that this effector protein is a suppressor of inflammasome responses. Further characterization indicated that this effector protein-mediated inhibition of inflammasome responses occurs at the level of gasdermin D, the pyroptotic executioner. Together, this study attributes a novel inflammasome inhibitory function to a Salmonella SPI-1 effector.

In vitro mRNA-S maternal vaccination induced altered immune regulation at the maternal-fetal interface.

Maternal-fetal immunology is intricate, and the effects of mRNA-S maternal vaccination on immune regulation at the maternal-fetal interface require further investigation. Our study endeavors to elucidate these immunological changes, enhancing our comprehension of maternal and fetal health outcomes. By analyzing immune profiles and cytokine responses, we aim to provide valuable insights into the impact of mRNA-S vaccination on the delicate balance of immune regulation during pregnancy, addressing critical questions in the field of reproductive pharmacology. This investigation sought to examine the prospective influence of mRNA-S-based vaccines and extracellular vesicles (EVs) containing the Spike (S) protein at the maternal-fetal interface. Our primary emphasis was on evaluating their effects on maternal decidua cells and fetal chorion trophoblast cells (hFM-CTCs). We validated the generation of EVs containing the S protein from small human airway epithelial cell lines (HSAECs) following mRNA-S vaccine exposure. We assessed the expression of angiotensin-converting enzyme 2 (ACE2) gene and protein in fetal membranes and the placenta, with specific attention to decidual cells and fetal membrane chorion cells. To assess cellular functionality, these cells were exposed to both recombinant S protein and EVs loaded with S proteins (eSPs). Our findings revealed that cells and EVs subjected to mRNA-S-based vaccination exhibited altered protein expression levels of S proteins. At the feto-maternal interface, both placental and fetal membrane tissues demonstrated similar ACE-2 expression levels. Among individual cellular layers, syncytiotrophoblast cells in the placenta and chorion cells in the fetal membrane exhibited elevated ACE-2 expression. Notably, EVs derived from HSAECs activated the MAPK pathway in decidual cells. Additionally, decidual cells displayed a substantial increase in gene expression of chemokines like CXCL-10 and CXCL-11, as well as proinflammatory cytokines such as IL-6 in response to eSPs. However, the levels of Ccl-2 and IL-1β remained unchanged in decidual cells under the same conditions. Conversely, hFM-CTCs demonstrated significant alterations in the proinflammatory cytokines and chemokines with respect to eSPs. In conclusion, our study indicates that mRNA-S-based maternal vaccination during pregnancy may influence the maternal-fetal interface's COVID-19 interaction and immune regulation. Further investigation is warranted to assess safety and implications.

Fibroblast growth factor receptor inhibitors mitigate the neuropathogenicity of Borrelia burgdorferi or its remnants ex vivo.

In previous studies, we showed that fibroblast growth factor receptors (FGFRs) contribute to inflammatory mediator output from primary rhesus microglia in response to live Borrelia burgdorferi. We also demonstrated that non-viable B. burgdorferi can be as pathogenic as live bacteria, if not more so, in both CNS and PNS tissues. In this study we assessed the effect of live and non-viable B. burgdorferi in inducing FGFR expression from rhesus frontal cortex (FC) and dorsal root ganglion (DRG) tissue explants as well as their neuronal/astrocyte localization. Specific FGFR inhibitors were also tested for their ability to attenuate inflammatory output and apoptosis in response to either live or non-viable organisms. Results show that in the FC, FGFR2 was the most abundantly expressed receptor followed by FGFR3 and FGFR1. Non-viable B. burgdorferi significantly upregulated FGFR3 more often than live bacteria, while the latter had a similar effect on FGFR1, although both treatments did affect the expressions of both receptors. FGFR2 was the least modulated in the FC tissues by the two treatments. FGFR1 expression was more prevalent in astrocytes while FGFR2 and FGFR3 showed higher expression in neurons. In the DRG, all three receptor expressions were also seen, but could not be distinguished from medium controls by immunofluorescence. Inhibition of FGFR1 by PD166866 downregulated both inflammation and apoptosis in both FC and DRG in response to either treatment in all the tissues tested. Inhibition of FGFR1-3 by AZD4547 similarly downregulated both inflammation and apoptosis in both FC and DRG in response to live bacteria, while with sonicated remnants, this effect was seen in one of the two FC tissues and 2 of 3 DRG tissues tested. CCL2 and IL-6 were the most downregulated mediators in the FC, while in the DRG it was CXCL8 and IL-6 in response to FGFR inhibition. Downregulation of at least two of these three mediators was observed to downregulate apoptosis levels in general. We show here that FGFR inhibition can be an effective anti-inflammatory treatment in antibiotic refractive neurological Lyme. Alternatively, two biologics may be needed to effectively curb neuroinflammation and pathology in the CNS and PNS.

WCN24-1847 Characterization of regulatory B cells and IL-10 in response to ischemic reperfusion

WCN24-1847 Characterization of regulatory B cells and IL-10 in response to ischemic reperfusion

Effects of a novel Bacillus subtilis GXYX crude lipopeptide against Salmonella enterica serovar Typhimurium infection in mice

The increased rate of antibiotic resistance strongly limits the resolution of Salmonella enterica serovar Typhimurium (S. Typhimurium) infection. Therefore, new strategies to control bacterial infections are urgently needed. Bacillus subtilis (B. subtilis) and its metabolites are desirable antibacterial agents. Here, we aimed to evaluate the antibacterial activity of the novel B. subtilis strain GXYX (No: PRJNA940956) crude lipopeptide against S. Typhimurium. In vitro, GXYX crude lipopeptides affected S. Typhimurium biofilm formation and swimming and attenuated the adhesion and invasion abilities of S. Typhimurium toward BHK-21 cells; in addition, it inhibited the mRNA expression of the filA, filC, csgA, and csgB genes, which are related to the adhesion and invasion ability of S. Typhimurium. In vivo, pretreatment with GXYX crude lipopeptide via intragastric administration improved the survival rate by 30%, which was related to reductions in organ bacterial loads and clinical signs in mice. Intragastric administration of GXYX crude lipopeptide significantly downregulated the mRNA levels of TNF-α, IL-1β, IL-12 and IL-6 in response to S. Typhimurium-induced inflammation compared with intraperitoneal injection. Moreover, it significantly improved the intestinal barrier-related gene (ZO-1, claudin-1, occludin-1) mRNA levels in intestinal tissue damaged by S. Typhimurium infection. In conclusion, GXYX crude lipopeptides were effective at reducing S. Typhimurium colonization, laying a foundation for the further development of novel antibacterial agents.