Cytotoxic T Lymphocytes Research Articles

CTIM-33. IMMUNE BIOMARKERS OF TREATMENT RELATED IMAGING CHANGES IN GLIOBLASTOMA PATIENTS TREATED WITH STANDARD OF CARE PLUS PEMBROLIZUMAB

Abstract Pseudoprogression is a post-treatment imaging phenomenon in glioblastoma (GBM) that mimics true progression. Immune checkpoint inhibition with pembrolizumab has shown clinical benefits in multiple cancers and is a burgeoning treatment in GBM. Discerning pseudoprogression, or treatment-related imaging changes, from true progression is essential for appropriate treatment recommendations. However, there are no reliable biomarkers that can differentiate between pseudoprogression and true progression. Our prospective single-arm study (NCT 03347617) evaluated immune cell sub-populations (B-cells, T-cells, NK cells, monocytes, and myeloid cells) in newly diagnosed GBM patients who received standard-of-care chemoradiation plus concurrent pembrolizumab after maximal safe resection. Flow cytometry was performed on blood collected at predetermined timepoints (pre-treatment, post-radiation, suspected progression, and confirmed progression) and immune cell sub-populations were evaluated as covariates in univariable and multivariable logistic regression analysis. Of the 56 patients enrolled in this trial, 51 completed blood collection. Median survival was 13.84 months. Fifteen (29%) patients had pseudoprogression by modified RANO criteria and 36 (70.5%) had suspected or confirmed progression. Univariable analysis identified the following serum derived immune populations as being significantly associated with pseudoprogression: cytotoxic T-cell percentage (CD3+CD8+; HR: 1.10; p=0.045); total NK Cells percentage (CD3+CD56+; HR:0.912; p=0.0.053); IGD+CD27-naïve B-cells of B-cell percentage (HR: 0.976; p=0.014); IGD+CD27+non-switched B of B-cell percentage (HR:1.07; p=0.036). Backward selection multivariable logistic regression analysis confirmed the significant association of cytotoxic T-cell percentage (CD3+CD8+; HR:1.02; p=0.049) with pseudoprogression while controlling for IGD+CD27+non-switched B of B-cell percentage (HR:1.01, p=0.116). Increasing levels of serum cytotoxic T-cells in GBM patients treated with standard-of-care plus pembrolizumab is associated with pseudoprogression and may be used to differentiate between true progression. Validation of results is needed in a control population treated with standard-of-care prior to clinical implementation. Future studies will utilize serum immune biomarkers coupled with radiomic features to better characterize the pseudoprogression signature in GBM.

IMMU-14. TRANS-SPECIES ANALYSIS OF REPLICATION-REPAIR DEFICIENT (RRD) MEDULLOBLASTOMA AND RESPONSE TO IMMUNE CHECKPOINT INHIBITION: AN IRRDC REPORT

Abstract BACKGROUND Replication-repair deficiency (RRD) stemming from mismatch repair and polymerase proofreading gene defects (MMRD/PPD) lead to hypermutant childhood cancers, most frequently brain tumors. While medulloblastoma is reported, the clinical, genomic and immune landscape remains unknown. METHODS We analysed the genome, methylome, transcriptome (bulk, single-nuclei) and immune-microenvironment of the largest cohort of RRD-medulloblastoma patients enrolled by the International RRD Consortium and correlated these to clinical outcomes. RRD mice-models were used to preclinically assess response to immunotherapy. Results: RESULTS RRD-medulloblastoma (n=43) were enriched for anaplasia (61%) and localised disease (77%). Methylation/nano-string-based subgrouping failed to classify 40%, while the remaining clustered with the SHH-subgroup. Copy-number changes were notably infrequent (<20%). All tumors harboured hypermutation and microsatellite instability in contrast to non-RRD controls (p<0.0001). Pathogenic variants were frequent in POLE/POLD1 (80%), TP53 (48%) and SHH-pathway genes (PTCH1, SUFU, SMO: 56%). Interestingly, some tumors additionally had glioma-driver alterations (ATRX, NF1: ~50%), similar to RRD cerebellar glioblastoma, but distinct from both non-RRD medulloblastoma (n=791) and hemispheric glioblastoma (n=733) controls. Moreover, although bulk-transcriptome matched non-RRD SHH medulloblastoma, single-nuclei analyses suggested an earlier cell-of-origin potentially explaining the heterogenous phenotypes resulting from the driver mutations. Uniquely, immune analyses (gene expression and immunohistochemistry) demonstrated high intra-tumoral CD8 T-cell infiltration. Three-year progression-free survival was 60%. Outcome was worse for RRD-medulloblastoma harbouring TP53-mutation (p=0.04) and failing subgroup-classification (p=0.004). Nestin/Cre MSH2-/- POLE;p.S459F mice developing medulloblastoma recapitulated human disease and demonstrated response to anti-PD1 monotherapy. Recurrent/progressive human tumors including those harbouring TP53-mutations exhibited radiological responses to anti-PD1 monotherapy, which was associated with prolonged ongoing survival in comparison to those not treated with checkpoint-inhibitors (p=0.02). CONCLUSIONS Hypermutant RRD-medulloblastoma reveal heterogenous phenotypes due to unique spectrum of driver mutations and an early cell of origin. Their immune-hot microenvironment allows successful salvage treatment with checkpoint-inhibitors for those failing chemo-radiation, including the high-risk SHH/TP53-mutant and unclassified subgroups.

PATH-35. INTEGRATED GENOMIC ANALYSES OF IMMUNODEFICIENCY-ASSOCIATED EPSTEIN-BARR VIRUS- (EBV) POSITIVE PRIMARY CNS LYMPHOMAS

Abstract Immunodeficiency-associated primary CNS lymphoma (PCNSL) represents a distinct clinicopathological entity, which is typically Epstein-Barr virus positive (EBV+) and carries an inferior prognosis. Genetic alterations that characterize EBV related CNS lymphomagenesis remain unclear precluding molecular classification and targeted therapies. In this study, a comprehensive genetic analysis of 22 EBV+ PCNSL, integrated clinical and pathological information with exome and RNA sequencing (RNASeq) data. Deconvolution of bulk RNA sequencing data was performed using CIBERSORTx to characterize the tumor microenvironment. EBV+ PCNSL with germline controls carried a median of 55 protein-coding single nucleotide variants (SNVs; range 24-217) and 2 insertions/deletions (range 0-22). Genetic landscape was largely shaped by aberrant somatic hypermutation with a median of 41.01% (range 31.79-53.49%) of SNVs mapping to its target motifs. Tumors lacked established SNVs (MYD88, CD79B, PIM1) and copy number variants (CDKN2A, HLA loss) driving EBV negative PCNSL. Instead, EBV+ PCNSL were characterized by SOCS1 mutations (26%), predicted to disinhibit JAK/STAT signaling, and mutually exclusive gain-of-function NOTCH pathway SNVs (26%). Copy number gains were enriched on 11q23.3, a locus directly targeted for chromosomal aberrations by EBV, that includes SIK3 known to protect from cytotoxic T-cell responses. Losses covered 5q31.2 (STING), critical for sensing viral DNA, and 17q11 (NF1). Unsupervised clustering of RNASeq data revealed two distinct transcriptional groups, that shared strong expression of CD70 and IL1R2, previously linked to tolerogenic tumor microenvironments. Correspondingly, deconvolution of bulk RNASeq data revealed elevated M2-macrophage, T-regulatory cell, mast cell and monocyte fractions in EBV+ PCNSL. In addition to novel insights into the pathobiology of EBV+ PCNSL, the data provide the rationale for the exploration of targeted therapies including JAK-, NOTCH- and CD70-directed approaches.

JAK-STAT1 as therapeutic target for EGFR deficiency-associated inflammation and scarring alopecia

AbstractThe hair follicle stem cell niche is an immune-privileged microenvironment, characterized by reduced antigen presentation, thus shielding against permanent immune-mediated tissue damage. In this study, we demonstrated the protective role of hair follicle-specific epidermal growth factor receptor (EGFR) against scarring hair follicle destruction. Mechanistically, disruption of EGFR signaling generated a cell-intrinsic hypersensitivity within the JAK-STAT1 pathway, which, synergistically with interferon gamma expressing CD8 T-cell and NK-cell-mediated inflammation, compromised the stem cell niche. Hair follicle-specific genetic depletion of either JAK1/2 or STAT1 or therapeutic inhibition of JAK1/2 ameliorated the inflammation, restored skin barrier function and activated the residual stem cells to resume hair growth in mouse models of epidermal and hair follicle-specific EGFR deletion. Skin biopsies from EGFR inhibitor-treated and cicatricial alopecia patients revealed an active JAK-STAT1 signaling signature along with upregulation of antigen presentation and downregulation of key components of the EGFR pathway. Our findings offer molecular insights and highlight a mechanism-based therapeutic strategy for addressing chronic folliculitis associated with EGFR-inhibitor anti-cancer therapy and cicatricial alopecia.

Spontaneous high clonal expansion of Wilms’ tumor gene 1-specific cytotoxic T-lymphocytes in patients with Wilms’ tumor gene 1-expressing solid tumor

Wilms’ tumor protein 1 (WT1)-targeted immunotherapy has been used in patients with leukemia and solid tumors. However, the spontaneous WT1-specific immune response before WT1 peptide vaccination in patients with WT1-expressing tumors (PTs) remains unclear. Therefore, we investigated whether WT1-specific cytotoxic CD8+ T-lymphocytes (CTLs) are clonally expanded in the peripheral blood outside of tumor sites. Clonal expansion of WT1126 peptide (a.a.126–134)-specific CTLs (WT1126-CTLs) was compared between seven PTs and five healthy volunteers (HVs), and their T-cell receptors (TCRs) were analyzed at the single-cell level. Overall, 433 and 351 TCR β-chains of WT1126-CTLs were detected from PTs and HVs, respectively, and complementarity-determining region 3 was sequenced for clonality analysis. The frequencies of WT1126-CTLs were higher in human leukocyte antigen (HLA)-A*02:01+ PTs than in HLA-A*02:01+ HVs, although the difference was not statistically significant. WT1126-CTLs of differentiated types, including memory and effector, were higher in PTs than in HVs; whereas, those of the naïve type were higher in HVs than in PTs. WT1126-CTL clonality was significantly higher in PTs than in HVs. Furthermore, the frequency of effector WT1126-CTLs positively correlated with WT1126-CTL clonality in PTs; whereas, the frequency of naïve phenotype WT1126-CTLs tended to be negatively correlated with clonality. In conclusion, these results suggest that the WT1 protein in tumor cells is highly immunogenic, thereby stimulating endogenous naïve-type WT1126-CTLs and enabling them to clonally expand and differentiate into effector-type WT1126-CTLs.

Burden of liver steatosis and liver fibrosis in a large cohort of people living with HIV.

Liver steatosis (LS) and liver fibrosis (LF) can increase the risk of cardiovascular disease in people with HIV, but their prevalence and associated factors are poorly understood. This study aimed to assess the prevalence of and factors associated with LS and LF in a large cohort of people with HIV. We conducted a cross-sectional study of consecutive people with HIV attending the Clinic of Barcelona from September 2022 to September 2023, excluding those with chronic B or/and C hepatitis virus coinfection. LS was assessed using the Hepatic Steatosis Index (HSI) and Fatty Liver Index (FLI), and LF was assessed using the Non-Alcoholic Fatty Liver Disease Fibrosis Score (NFS), Fibrosis-4 score (FIB-4), and the European AIDS Clinical Society (EACS) algorithm in both the whole cohort (cohort 1) and in a specific cohort more susceptible to liver disease (cohort 2). We identified independent variables associated with LS and LF using logistic regression. Cohort 1 included 4664 people with HIV; 76% and 37% of them had available HSI and FLI data, LS was present in 28% and 19%, respectively. LF risk was present in 1%, 2%, and 1% of people with HIV according to NFS, FIB-4, and EACS algorithm scores, respectively. Cohort 2 included 1345 people with HIV; 60% and 30% of them had available HSI and FLI data, LS affected 55% and 43% and LF 2%, 5%, or 3%, respectively. Factors associated with LS included current CD4 cell count, diabetes, and hypertension, whereas LF was associated with previous exposure to dideoxynucleoside drugs and current CD4 to LF. Current integrase strand transfer inhibitor (INSTI) therapy appeared protective for LF in cohort 1. In this study, one in four people with HIV had LS, and the prevalence rose to one in two in those with cardiovascular risk factors. The prevalence of LF was low, but it should be considered in older people with HIV with low CD4 counts or high aspartate transaminase levels. A possible protective effect from INSTIs deserves further investigation.

A B7-H3–Targeted CD28 Bispecific Antibody Enhances the Activity of Anti–PD-1 and CD3 T-cell Engager Immunotherapies

Abstract T-cell activation is a multistep process requiring T-cell receptor engagement by peptide–MHC complexes (Signal 1) coupled with CD28-mediated costimulation (Signal 2). Tumors typically lack expression of CD28 ligands, so tumor-specific Signal 1 (e.g., neoepitope presentation) without costimulation may be ineffective or even induce T-cell anergy. We designed the bispecific antibody XmAb808 to co-engage the tumor-associated antigen B7-H3 with CD28 to promote T-cell costimulation within the tumor microenvironment. XmAb808 costimulation was measured by its ability to activate and expand T cells and enhance T cell–mediated cancer cell killing in cocultures of human peripheral blood mononuclear cells and cancer cells and in mice engrafted with human peripheral blood mononuclear cells and tumor xenografts. XmAb808 avidly bound cancer cells and stimulated IL2 and IFNγ secretion from T cells cocultured with cancer cells engineered to deliver Signal 1 to T cells via a surface-expressed anti-CD3 antibody. XmAb808 enhanced expression of the antiapoptotic factor Bcl-xL and CD25, promoting survival and IL2-dependent expansion of T cells coupled with increased T cell–mediated cytotoxicity in vitro. XmAb808 combined with an EpCAM×CD3 bispecific antibody to enhance target cell killing through IL2-dependent expansion of CD25+ T cells. This combination also suppressed pancreatic tumor xenograft growth in mice. Furthermore, XmAb808 combined with an anti–programmed cell death protein 1 antibody to suppress breast tumor xenograft growth in mice. XmAb808 as monotherapy and in combination with an anti–programmed cell death protein 1 antibody is currently in clinical development in patients with advanced solid tumors. Our results suggest that XmAb808 may also combine with tumor antigen–targeted anti-CD3 (Signal 1) T-cell engagers.

Association among therapeutic adherence, health literacy, and engagement in care: How to increase health-conscious management of HIV disease.

In the context of People Living with HIV (PLWH), poor health literacy (HL) seems to be linked to poorer health outcomes and reduced engagement in care. Additionally, the level of HL can affect HIV knowledge and may impact adherence to antiretroviral therapy (ART). This research explored the connection between ART adherence, HL, and engagement in care in a cohort of 250 PLWH receiving ART in Italy. A questionnaire was given to PLWH at Policlinico Gemelli in Rome to assess their health literacy and adherence to therapy. The Brief Health Literacy Screening (BHLS) and the Newest Vital Sign (NVS) were used to evaluate subjective and objective HL. Adherence levels were self-reported as poor, good, or excellent, and the assessment included the Patient Health Engagement Scale (PHE-S). Notably, the majority of the sample comprised male individuals (67.9%), with 69.2% reporting a 10-years or longer duration between their HIV diagnosis and their initiation of ART. It was found that PLWH with poor adherence had low schooling, had been living with HIV for 1-5years, were HCV co-infected, had a viremia >50copies/mL, poor health status, poor engagement in care, and poor HL (p = <0.001). They exhibited lower mean scores on the subjective HL scale and lower CD4 T-cell counts and nadir CD4 T-cell counts (p < .001). Our study demonstrated a positive correlation between higher HL levels and improved disease management, treatment adherence, and overall physical and mental well-being. Enhanced HL capabilities are paramount in bolstering health management and treatment adherence.

Two-Drug Combination Antiretroviral Therapy for HIV-1: Case Series and Literature Review

Background: Doravirine (DOR) is a non-nucleoside reverse transcriptase inhibitor (NNRTI) approved for use in combination antiretroviral therapy (cART) for treatment of human immunodeficiency virus (HIV) in treatment-naive patients. Doravirine-based regimens are an option for patients with limited alternatives due to drug-drug interactions, toxicities, or resistance. A paucity of data exists for use of two-drug DOR-based regimens in treatment-experienced individuals. Methods: This is a retrospective case series of two treatment-experienced HIV-1 infected patients switched to two-drug doravirine-based regimens. Baseline HIV-RNA and CD4 cell count were measured at the time of switch to the DOR-based regimen. HIV-RNA and CD4 cell count were measured again more than a month after initiating therapy to determine efficacy of the DOR-based regimens. Results: Patient 1 was transitioned to once daily DOR and darunavir with cobicistat (DRV/c). The baseline HIV-RNA was 370,070 copies/mL and CD4 cell count was 196 cells/mm3. After 2 years of treatment, the viral load was less than 30 copies/mL and the CD4 cell count was 239 cells/mm3. Patient 2 was transitioned to once daily DOR and dolutegravir (DTG). The baseline HIV-RNA was &lt;30 copies/mL and CD4 cell count was 229 cells/mm3. After 11 months of therapy, the patient’s HIV viral load remained &lt;30 copies/mL and the CD4 cell count was stable at 236 cells/mm3. Conclusions: Two-drug cART including DOR appears to be an acceptable option for patients who may be limited to alternative ART regimens due to drug-drug interactions, resistance mutations, or toxicities. Additional evidence from case reports or clinical trials are needed to further evaluate the long-term efficacy and safety of DOR as part of a two-drug cART regimen.

Mycobacterium avium complex (MAC) infection in severely immunocompromised people living with HIV: Findings from a five-year cohort.

We sought to clarify the current incidence, risk factors and symptoms of disseminated Mycobacterium avium complex (dMAC) infection in admitted people living with HIV in a hospital in the Southeast of Spain. 5-years observational, retrospective and single-centre study. Demographic, clinical and analytical variables, along with microbiological, treatment and follow-up were collected. Five cases of dMAC infection in severely immunocompromised people living with HIV people living were found. dMAC was diagnosed in 22.7% of patients under 100 CD4. All patients presented with fever and clinical manifestations of pneumonia, lymphadenopathy, or gastrointestinal symptoms. Despite low CD4 levels and high viral loads in some cases, primary prophylaxis had not been previously administered. Until 2018, U.S. American guidelines recommended antimycobacterial prophylaxis for patients with low CD4 cell counts, a practice not adopted in Europe. Untreated dMAC infection is associated with high morbidity and mortality rates. dMAC infection represents a prevalent disease in severely immunosuppressed people living with HIV. dMAC requires a high index of suspicion in this population, in order to perform mycobacterial cultures from different samples.

Judy Lieberman: Stay curious and excited about science.

Judy Lieberman is a professor of pediatrics and adjunct professor of genetics at Harvard Medical School and an endowed chair in cellular and molecular medicine. Her lab studies cytotoxic T lymphocytes (CTL), key cells in the immune defense against viral infection and cancer, as well as molecular pathways activated by the granzymes, and how RNA interference (RNAi) regulates cell differentiation in health and disease states. We spoke to Judy about advice for early career researchers, how she first become interested in cytotoxic T lymphocytes, and key people who have provided mentorship across her career.

Antigen-specific modulation of chronic experimental autoimmune encephalomyelitis in humanized mice by TCR-like antibody targeting autoreactive T-cell epitope.

The development and application of human TCR-like (TCRL) antibodies recognizing disease-specific MHC-peptide complexes mayprove asan important tool for basic research and therapeutic applications. Multiple sclerosis is characterized by aberrant CD4 T-cell response to self-antigens presented by MHC class II molecules. This led us to select a panel of TCRL Abs targeting the immunodominant autoantigenic epitope MOG35-55 derived from myelin oligodendrocyte glycoprotein (MOG) presented on HLA-DR2, which is associated with multiple sclerosis (MS). We demonstrate that these TCRL Abs bind with high specificity to human HLA-DR2/MOG35-55-derived MHC class II molecules and can detect APCs that naturally present the MS-associated autoantigen in the humanized EAE transgenic mouse model. The TCRL Abs can block ex vivo and in vivo CD4 T-cell proliferation in response to MOG35-55 stimulation in an antigen-specific manner. Most significantly, administration of TCRL Abs to MOG35-55-induced EAE model in HLA-DR2 transgenic mice both prevents and regresses established EAE. TCRL function was associated with a reduction in autoreactive pathogenic T-cell infiltration into the CNS, along with modulation of activated CD11b+ macrophages/microglial APCs. Collectively, these findings demonstrate the combined action of TCRL Abs in blocking TCR-MHC interactions and modulating APC presentation and activation, leading to a profound antigen-specific inhibitory effect on the neuroinflammatory process, resulting in regression of EAE. Our study constitutes an in vivo proof of concept for the utility of TCR-like antibodies as antigen-specific immunomodulators for CD4-mediated autoimmune diseases such as MS, validating the importance of the TCR-MHC axis as a therapeutic target for various autoimmune and inflammatory diseases.

Recent advances in immunotherapy for small cell lung cancer

Purpose of review This review aims to provide an overview of recent advances in immunotherapy for small cell lung cancer (SCLC), with a focus on the current status of immune checkpoint inhibitors (ICIs), novel combination strategies, and key biomarkers. Recent findings The integration of ICIs into standard chemotherapy has established them as the first-line treatment for extensive-stage SCLC (ES-SCLC). The ADRIATIC trial further demonstrated the efficacy of ICI maintenance therapy in limited-stage SCLC. Additionally, combining radiotherapy with ICIs has shown promising synergistic effects, including the abscopal and radscopal effects. Ongoing investigations into the combination of ICIs with targeted therapies, such as antiangiogenic agents and DNA damage response inhibitors, have yielded encouraging preliminary results. Notably, the novel therapeutic agent tarlatamab, the first bispecific DLL3-directed CD3 T-cell engager, has recently received FDA approval for second-line treatment of ES-SCLC. Advances in omics technologies have shed light on the intra-tumor and inter-tumor heterogeneity of SCLC, leading to the identification of new molecular subtypes and biomarkers, thereby paving the way for precision medicine. Summary Despite the improved outcomes associated with immunotherapy in SCLC, the overall clinical benefit remains modest. Further preclinical and clinical studies are essential to identify optimal treatment regimens and enhance therapeutic efficacy.

Designing a multi-epitope subunit vaccine against Toxoplasma gondii through reverse vaccinology approach

The parasite Toxoplasma gondii, or T. gondii, is zoonotic that both individuals as well as animals can contract resulting in toxoplasmosis, a life-threatening illness. We used an immunoinformatic technique in our research to construct a vaccine with multi-epitopes so that it can decrease the devastating impact caused by this dangerous parasite. In order to construct the vaccine, GRA6 and MIC3 proteins were targeted, which are engaged in T. gondii identification, infection, and immune response. Novel epitopes for linear B lymphocytes (LBL), cytotoxic T lymphocytes (CTL), and helper T lymphocytes (HTL) were found by epitope mapping, every anticipated epitope was assessed through rigorous screening to determine the top choices for epitopes which were entirely preserved, very antigenic in nature, nonallergenic, and nontoxic. 4 CTLs, 3 HTLs and 4 LBL epitopes were chosen and combined along with proper linkers and adjuvants to design a vaccine with several epitopes. Linkers as well as adjuvants were provided to make the vaccine more immunogenic, antigenic, and stable. The proposed vaccination was identified to possess the necessary biophysical properties, be soluble, extremely antigenic, and non-allergic. Reliability of the vaccine design was demonstrated by secondary along with tertiary structure prediction. It was anticipated that the vaccine's three-dimensional structure would likely link up with TLR-2 and TLR-4 via the investigation of molecular docking. TLR-2 and TLR-4 are crucial for the parasite's invasion and the body's response. In our docking investigation, both TLRs demonstrated strong binding affinities utilizing the vaccine structure. After that, the vaccine construct's elevated expression rate, which was observed in Escherichia coli strain K12, was confirmed by an investigation using in silico cloning and codon adaptation. The results of the research are really encouraging and some properties of the vaccine were found to be significantly better than existing the T. gondii multi-epitope vaccination based on the same proteins. Nonetheless, in vivo trials are strongly suggested for potential future studies.

The pore-forming apolipoprotein APOL7C drives phagosomal rupture and antigen cross-presentation by dendritic cells.

Conventional dendritic cells (cDCs) generate protective cytotoxic T lymphocyte (CTL) responses against extracellular pathogens and tumors. This is achieved through a process known as cross-presentation (XP), and, despite its biological importance, the mechanism(s) driving XP remains unclear. Here, we show that a cDC-specific pore-forming protein called apolipoprotein L 7C (APOL7C) is up-regulated in response to innate immune stimuli and is recruited to phagosomes. Association of APOL7C with phagosomes led to phagosomal rupture and escape of engulfed antigens to the cytosol, where they could be processed via the endogenous MHC class I antigen processing pathway. Accordingly, mice deficient in APOL7C did not efficiently prime CD8+ T cells in response to immunization with bead-bound and cell-associated antigens. Together, our data indicate the presence of dedicated apolipoproteins that mediate the delivery of phagocytosed proteins to the cytosol of activated cDCs to facilitate XP.

Inhibition of Notch enhances efficacy of immune checkpoint blockade in triple-negative breast cancer.

Aberrant Notch, which is a defining feature of triple-negative breast cancer (TNBC) cells, regulates intercellular communication in the tumor immune microenvironment (TIME). This includes tumor-associated macrophage (TAM) recruitment through Notch-dependent cytokine secretion, contributing to an immunosuppressive TIME. Despite the low response rate of TNBC to immune checkpoint blockade (ICB), here, we report that inhibition of Notch-driven cytokine-mediated programs reduces TAMs and induces responsiveness to sequentially delivered ICB. This is characterized by the emergence of GrB+ cytotoxic T lymphocytes (CTLs) in the primary tumor. A more impressive effect of sequential treatment is observed in the lung where TAM depletion and increased CTLs are accompanied by near-complete abolition of metastases. This is due to (i) therapeutic reduction in Notch-dependent, prometastatic circulating factors released by the primary tumor, and (ii) elevated PD ligand 1 (PD-L1) in lung metastases, rendering them profoundly sensitive to ICB. These findings highlight the potential of combination cytokine inhibition and ICB as an immunotherapeutic strategy in TNBC.

The immune responses elicited by six recombinant antigens of Mycoplasma hyopneumoniae in mice

Mycoplasma hyopneumoniae (M. hyopneumoniae) is the causative agent of swine enzootic pneumonia, resulting in substantial economic losses in global pig farming. Although vaccination is the primary strategy for controlling M. hyopneumoniae infection, current vaccines fall short in preventing transmission of this pathogen or protecting the body from secondary infection. This study aimed to assess the immunogenicity of six recombinant antigens (P97R1, P46, GAPDH, PdhA, DnaK, and EF-Tu) of M. hyopneumoniae through intramuscular immunization in mice. The results showed that the six antigens elicited high levels of serum IgG. Among them, P97R1, P46, PdhA, and DnaK stimulated robust antigen-specific IgA mucosal immune responses. CCK-8 assays revealed that both P97R1 and DnaK significantly increased the proliferation of mononuclear cells from spleen and lung, and DnaK also promoted the proliferation of blood mononuclear cells. Additionally, PdhA induced Th17-type immune response with a high level of IL-17 level in serum. Flow cytometry analysis indicated that P97R1 and PdhA increased the ratio of CD8+/CD4+ T lymphocyte, favoring cytotoxic T lymphocyte (CTL) immune responses. Notably, P97R1 immunization significantly decreased the percentages of CD4+ T cells while increased the percentages of CD8+ T cells. The present findings demonstrate that the candidate antigens P97R1, PdhA, and DnaK of M. hyopneumoniae induce specific humoral and mucosal immunity; P97R1 and DnaK also stimulated intense cellular immunity, and PdhA induced CTL and Th17-type immune responses. In conclusion, P97R1, PdhA, and DnaK emerge as potential candidate antigens for the future development of a more effective subunit vaccine against M. hyopneumoniae.

Transcription factor networks drive perforin activity in the anti-bacterial immune response of tilapia

Perforin, produced by natural killer (NK) cells and cytotoxic T lymphocytes (CTLs), is one of the effectors of cell-mediated cytotoxicity (CMC) in vertebrates, playing a paramount role in killing target cells. However, whether and how perforin is involved in adaptive immune responses in early vertebrates remains unclear. Using Nile tilapia (Oreochromis niloticus) as a model, we investigated the characteristics of perforin in early vertebrates. Oreochromis niloticus perforin (OnPRF) possesses 2 conserved functional domains, membrane attack complex/perforin (MACPF) and protein kinase C conserved region 2 (C2) domains, although they share low amino acid sequence similarity with other homologs. OnPRF was widely expressed in various immune tissues and could respond to lymphocyte activation and T-cell activation in vitro at both the transcriptional and protein levels, indicating that it may be involved in adaptive immune responses. Furthermore, after infection with Edwardsiella piscicida and Aeromonas hydrophila, the mRNA and protein levels of OnPRF were significantly up-regulated within the adaptive immune response period. Additionally, we revealed that many transcription factors were involved in the transcriptional regulation of OnPRF, including p65, c-Fos, c-Jun, STAT1 and STAT4, and there was a synergy among these transcription factors. Overall, these findings demonstrate the involvement of OnPRF in T-cell activation and adaptive immune response in tilapia, thus providing new evidence for comprehending the evolution of immune response in early vertebrates.

Evaluating the Impact of Adjunctive Partial Cryoablation on Dual Checkpoint Inhibitor Immunotherapy Response in a Murine Model.

Purpose To evaluate the impact of adjunctive partial cryoablation on checkpoint inhibitor (CPI) immunotherapy response. Materials and Methods One hundred fifty-six mice (equal number of male and female animals) with dual-implanted tumor models were treated with dual CPI or a vehicle and randomized to treatment of a single tumor with partial cryoablation. Tumors were followed for 60 days following cryoablation for response assessment. In additional groups, the tumor microenvironment was characterized via flow cytometry, cytokine analysis, and immunohistochemistry. Statistical comparison was made between the different treatment groups regarding T-cell infiltration and activation characteristics within the noncryoablated tumor and cytokine levels within the partially ablated tumor. Additionally, qualitative assessment of T-cell activation within the cryoablated and noncryoablated tumors at immunofluorescence was carried out. Results At 60 days following treatment, CPI and adjunctive cryoablation-treated MC-38 mice had a significantly increased survival rate (79%) compared with mice treated with CPI alone (61%; P < .001). CT-26 mice also had an increased survival rate (57% vs 35%, respectively; P = .04). Following cryoablation, increases in inflammatory cytokines and chemokines within the treated tumors were observed. Flow cytometry of noncryoablated tumor showed increased CD8 T-cell activation. Immunofluorescence and histologic evaluation following cryoablation further demonstrated a robust CD8 T-cell and myeloid infiltrate. Conclusion Adjunctive cryoablation significantly increased the response to dual CPI in multiple cancer models at both partially ablated and distant (nonablated) tumor sites. Immune analysis suggests cryoablation promotes a vigorous immune response within the partially cryoablated tumor that increases activation of the adaptive immune system within distant tumor sites. Keywords: Cancer, Cryoablation, Checkpoint Inhibitor Immunotherapy, Tumor Response Supplemental material is available for this article. © RSNA, 2024.

Enhanced cancer cell proliferation and aggressive phenotype counterbalance in breast cancer with high BRCA1 gene expression.

While comprehensive research exists on the mutation of the DNA repair gene BRCA1, limited information is available regarding the clinical significance of BRCA1 gene expression. Given that cancer cell proliferation is aggrevated by DNA repair, we hypothesized that high BRCA1 gene expression breast cancer (BC) might be linked with aggressive tumor biology and poor clinical outcomes. The cohorts: The Cancer Genome Atlas (TCGA, n = 1069), METABRIC (n = 1903), and SCAN-B (n = 3273) were utilzed to obtain data of 6245 BC patients. BC patients without BRCA1 mutation exhibited higher BRCA1 expression, which was associated with DNA repair functionality. However, no such correlation was observed with BRCA2 expression. The association of high BRCA1 expression with cancer cell proliferation was evidenced by significant enrichment of cell proliferation-related gene sets, higher histological grade, and proliferation score. Furthermore, increased levels of homologous recombination deficiency, intratumoral heterogeneity, and altered fractions were associated with high BRCA1 expression. Moreover, BC with high BRCA1 expression exhibited reduced infiltration of dendritic cells and CD8 T-cells, while showing increased infiltration of Th1 cells. Surprisingly, BRCA1 expression was not associated with the survival of BC irrespective of the subtypes. Conversely, BC with low BRCA1 expression enriched cancer aggravating pathway gene sets, such as Cancer Stem Cell-related signaling (NOTCH and HEDGEHOG), Angiogenesis, Epithelial-Mesenchymal Transition, Inflammatory Response, and TGF-beta signaling. Despite being linked to heightened proliferation of cancer cells and unassertive phenotype, BRCA1 expression did not show any association with survival in BC.