Human Leukocyte antigen-A Research Articles

Activation of non-classical Wnt signaling pathway effectively enhances HLA-A presentation in acute myeloid leukemia.

The escape from T cell-mediated immune surveillance is an important cause of death for patients with acute myeloid leukemia (AML). This study aims to identify clonal heterogeneity in leukemia progenitor cells and explore molecular or signaling pathways associated with AML immune escape. Single-cell RNA sequencing (scRNA-seq) was performed to identified AML-related cellular subsets, and intercellular communication was analyzed to investigate molecular mechanisms associated with AML immune escape. Bulk RNA sequencing (RNA-seq) was performed to screen differentially expressed genes (DEGs) related to hematopoietic stem cell progenitors (HSC-Prog) in AML, and critical ore signaling pathways and hub genes were found by Gene Set Enrichment Analysis (GSEA), Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis. The mRNA level of the hub gene was verified using quantitative real-time PCR (qRT-PCR) and the protein level of human leukocyte antigen A (HLA-A) using enzyme-linked immuno sorbent assay (ELISA). scRNA-seq analysis revealed a large heterogeneity of HSC-Prog across samples, and the intercellular communication analysis indicated a strong association between HSC-Prog and CD8+-T cells, and HSC-Prog also had an association with HLA-A. Transcriptome analysis identified 1748 DEGs, enrichment analysis results showed that non-classical wnt signaling pathway was associated with AML, and 4 pathway-related genes (RHOA, RYK, CSNK1D, NLK) were obtained. After qRT-PCR and ELISA validation, hub genes and HLA-A were found to be down-regulated in AML and up-regulated after activation of the non-classical Wnt signaling pathway. In this study, clonal heterogeneity of HSC-Prog cells in AML was identified, non-classical wnt signaling pathways associated with AML were identified, and it was verified that HLA-A could be upregulated by activation of non-classical wnt signaling, thereby increasing antigen presentation.

Open-label, phase 1, multicenter study to evaluate the safety and preliminary anti-tumor activity of NT-175 in human leukocyte antigen-a*02:01-positive adult subjects with unresectable, advanced and/or metastatic solid tumors that are positive for the TP53 R175H mutation.

e14514 Background: The TP53 tumor suppressor gene is the most commonly mutated gene across all cancer types, and TP53 R175H is the most common recurrent mutation across indications, identified in 6.7% of patients with breast cancer, 6% of patients withs colorectal cancer, and 4.2% of patients with pancreatic cancer. No therapy is approved for treatment directly targeting TP53 R175H. NT-175 is an armored autologous T-cell product expressing an HLA-A*02:01-restricted TCR recognizing TP53 R175H with disruption of the endogenous TCR and the transforming growth factor beta receptor type 2 (TGFBR2) genes. Methods: This first-in-human phase I, open label study will assess the safety and preliminary anti-tumor activity, identify the maximum tolerated dose (MTD), and evaluate the persistence, and functional capacity of NT-175 in subjects with advanced, recurrent unresectable/metastatic solid tumors refractory to treatment options. The study will enroll approximately 24 subjects harboring TP53 R175H and HLA-A*02:01. Enrolled patients will undergo leukapheresis from which CD4 and CD8 T cells will be enriched and activated ex vivo. The endogenous TCR α and β chain gene are knocked out utilizing clustered Regularly Interspaced Short Palindromic repeats (CRISPR-Cas9) and the TCR encoding an HLA-A*02:01-restricted TCR specific to the TP53 R175H mutation is inserted in the TCR α locus. Additionally, the T cells are edited to disrupt the gene encoding the TGFBR2 to reduce the immunosuppressive effect of TGF-β in the tumor microenvironment. Subjects will undergo lymphodepletion chemotherapy with fludarabine and cyclophosphamide followed by a single infusion of NT-175 and subcutaneous recombinant IL-2 administration for up to 8 days. Dose escalation will occur across 3 ascending dose levels following the BOIN design. Subjects will be monitored for dose-limiting toxicities for 28 days after NT-175 infusion. Tumor response will be assessed by RECISTv1.1 criteria. All subjects will be followed for up to 15 years. Primary endpoints include safety, dose limited toxicities, MTD determination, and recommended Phase II dose. Secondary endpoints include preliminary efficacy measures. Translational analysis will evaluate potential biomarkers for insights into mechanism of action, response prediction, or resistance mechanisms. The study was activated in March 2023 and is open to accrual; 5 patients have been enrolled as of 4 Jan 2024.

Improving ethnic and racial diversity in biomarker-driven clinical trials: A proof of concept with the BASECAMP-1 master prescreening study of patients with high-risk solid tumors with human leukocyte antigen-A*02 (HLA-A*02) loss of heterozygosity (LOH).

1604 Background: Diversity in clinical studies is essential to address health disparities, but racial and ethnic minorities are often underrepresented in clinical studies, especially in precision medicine studies using genetic data (1). BASECAMP-1 (NCT04981119) is an ongoing prescreening study to identify patients with unresectable advanced or metastatic solid tumors and tumor-associated HLA-A*02 LOH for the EVEREST-1 and -2 Tmod chimeric antigen receptor T-cell therapy trials. When enrollment began in 2021, eligibility for Part 1 was restricted to patients with germline HLA-A*02:01 based on preclinical data. Additional analysis revealed the blocker in the Tmod construct had activity across HLA-A*02 subtypes (Mock, et al. Mol Ther Oncolytics.2022). Eligibility for Part 1 was then expanded to all HLA-A*02 subtypes, allowing enrollment of more diverse patient populations. HLA-A*02 allele subtypes vary by ethnicity and race; the frequency of HLA-A*02:01 is 96% in non-Hispanic Whites, but ranges from 53% to 73% in other ethnicities and races. The frequency of all other HLA-A*02 allele subtypes (HLA-A*02:XX) is <5% in non-Hispanic Whites but up to 66% in other ethnicities and races (2,3). Methods: Patients eligible for BASECAMP-1 were identified at United States study sites. All patients screened before January 16, 2024, for Part 1 were included for demographic and central lab HLA-A typing. The % increase in eligibility and % of heterozygous HLA-A*02 patients with HLA-A*02:XX were calculated by ethnicity and race. Results: A total of 1124 patients were screened for germline HLA-A*02 typing; 431 patients were HLA-A*02:01 heterozygous, of whom 37 (9%) were Hispanic, 14 (3%) African American (AA), 2 (<1%) American Indian or Alaska Native, 17 (4%) Asian or Pacific Islander (API), and 324 (75%) non-Hispanic White (Table). The eligibility expansion identified 62 patients with HLA-A*02:XX heterozygosity, of whom 6 (10%) were Hispanic, 6 (10%) AA, 19 (31%) API, and 25 (40%) non-Hispanic White. Conclusions: By expanding enrollment to include HLA-A*02:XX, 16% more Hispanic, 43% more AA, and 112% more API patients were identified, improving the diversity in this trial compared with that of initial enrollment. 1. Aldrighetti, et al. JAMA Netw Open 2021. 2. Ellis, et al. Human Immunol. 2000. 3. Gragert, et al. Human Immunol.2013. Clinical trial information: NCT04981119 . [Table: see text]

LILRB2 promotes immune escape in breast cancer cells via enhanced HLA-A degradation.

Increased expression of leukocyte immunoglobulin-like receptor subfamily B member 2 (LILRB2) is associated with immune evasion in breast cancer (BC). The aim of this study to elucidate the role of LILRB2 in BC progression. LILRB2 expression in tumor tissues was detected by immunohistochemical staining. Human leukocyte antigen A (HLA-A) expression in BC cells was detected by Western blotting, and HLA-A ubiquitination was detected by immunoprecipitation and histidine pulldown assay. An in-situ tumor model was established in nude BALB/c mice to verify the role of LILRB2 in immune escape. Finally, the functions and potential mechanisms of LILRB2 in BC progression were explored using in silico data. LILRB2 was upregulated in BC tissues and cells, and correlated positively with poor prognosis. LILRB2 promoted BC progression by downregulating HLA-A expression. Mechanistically, LILRB2 facilitates the ubiquitination and subsequent degradation of HLA-A by promoting the interaction between the ubiquitin ligase membrane-associated ring finger protein 9 (MARCH9) and HLA-A. In syngeneic graft mouse models, LILRB2-expressing BC cells evaded CD8 + T cells and inhibited the secretion of cytokines by the cytotoxic CD8 + T cells. LILRB2 downregulates HLA-A to promote immune evasion in BC cells and is a promising new target for BC treatment.

A novel method for identifying SARS-CoV-2 infection mutants via an epitope-specific CD8+ T cell test

Since the outbreak of the coronavirus disease 2019 (COVID-19) epidemic in 2019, the public health system has faced enormous challenges. Tracking the individuals who test positive for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a key step for interrupting chains of transmission of SARS-CoV-2 and reducing COVID-19-associated mortality. With the increasing of asymptomatic infections, it is difficult to track asymptomatic infections through epidemiological surveys and virus whole-genome sequencing. However, due to the cross-reactivity of neutralizing antibodies produced by multiple virus subtypes, neutralizing antibody detection cannot be used to determine whether an individual has a history of infection with a specific subtype of SARS-CoV-2. We recruited 4 human leukocyte antigen A2 (HLA-A2) infections, 15 individuals who received three doses of inactivated vaccines, and 30 breakthrough infections after vaccination and discussed a case-tracking approach to detect epitope-specific CD8+ T cells in the peripheral blood of close contacts, including accurate HLA typing based on ribonucleic acid (RNA)-sequencing and flow cytometry data and the comparison and characterization of SARS-CoV-2 HLA-A2 and HLA-A24 epitope-specific CD8+ T cells. From individuals who received three doses of inactivated vaccine, we observed that the CD8+ T cell specificity for ancestral epitopes was significantly higher than for mutated epitopes, and the fold change of CD8+ T cells corresponding to mutated epitopes relative to ancestral epitopes was less than 1. The enzyme-linked immunospot (ELISpot) results further validate this result. This study forms a “method for understanding the infection history of SARS-CoV-2 subtypes based on the proportion of epitope-specific CD8+ T cells in the peripheral blood of subjects”, covering up to 46 % of the population, including HLA-A2+ and HLA-A24+ donors, providing a novel method for SARS-CoV-2 infected case tracing.

Abstract B034: Characterization of MHC-I-mediated immune evasion in triple-negative breast cancer using human transcriptomic datasets and immunocompetent mouse models

Abstract In Triple-Negative Breast Cancer (TNBC) patients, adaptive immune system activity in the tumor microenvironment is associated with improved prognosis. However, tumors can evolve to evade immune detection, likely leading to worse patient outcomes. Multi-omic data of paired primary and metastatic breast tumors demonstrate that TNBC metastases frequently lose expression of genes involved in major histocompatibility complex class I (MHC-I) antigen presentation, a key pathway for adaptive immune activation (PMID: 36585450). Therefore, understanding and addressing MHC-I-mediated immune evasion may have profound clinical benefits for TNBC patients. We hypothesize that breast tumor MHC-I loss results in a unique immune-evasive phenotype, which we are characterizing using human clinical datasets and immunocompetent mouse models of breast cancer. First, using large transcriptomic datasets (i.e., SCAN-B and TCGA), we are characterizing molecular and clinical features of MHC-I-low human breast tumors using expression of the MHC-I gene human leukocyte antigen A (HLA-A) as a continuous variable. We found HLA-A expression varies significantly between PAM50 molecular and clinical subtypes of breast cancer and has differing impacts on patient survival based on clinical subtype. In TNBCs, low HLA-A expression is associated with worse outcomes, while in HR+/HER2- tumors, low HLA-A predicts improved outcomes. We also identified genes highly correlated with HLA-A regardless of molecular subtype. This list was functionally rich, related to antigen processing machinery, adaptive immune-mediated cytotoxicity, and T cell exhaustion features. To complement human genomic data, we are empirically testing the role of MHC-I in syngeneic mouse mammary tumor models by individually knocking out murine MHC-I genes–H2-K, H2-D, and B2m–through CRISPR/Cas9-mediated genome editing. We have generated and validated knockouts (KOs) of H2-K and B2m, as well as empty vector control clones from the “immune-hot” and immune checkpoint inhibitor (ICI) responsive mammary tumor cell lines KPB25L-UV and T11-APOBEC. RNA sequencing of KPB25L-UV H2-K and B2m KO versus wildtype cell lines in vitro identified lists of differentially expressed genes, many of which are related to proteolytic and peptide antigen processing. Next, these CRISPR-modified cell lines were injected into the mammary fat pad of syngeneic immunocompetent mice, and the resulting tumors were harvested for RNA sequencing. Differentially expressed genes in KPB25L-UV H2-K KO versus wildtype tumors were related to increased MHC Class II antigen presentation and dendritic cell activity. Preliminary data suggests that mice bearing KPB25L-UV H2-K KO tumors have shortened survival compared to H2-K wildtype tumors. Experiments are ongoing to further characterize the growth dynamics, metastatic potential, single-cell transcriptomic profiles, and ICI sensitivities of these KO tumors in vivo. Our long-term goal is to identify therapeutic means to overcome this common immune-evasive phenotype to improve TNBC patient outcomes. Citation Format: Constandina E O'Connell, Brooke M Felsheim, Aranzazu Fernandez-Martinez, Kevin R Mott, Charles M Perou. Characterization of MHC-I-mediated immune evasion in triple-negative breast cancer using human transcriptomic datasets and immunocompetent mouse models [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Advances in Breast Cancer Research; 2023 Oct 19-22; San Diego, California. Philadelphia (PA): AACR; Cancer Res 2024;84(3 Suppl_1):Abstract nr B034.

Practical guidelines for the management of adverse events of the T cell engager bispecific tebentafusp

Tebentafusp is a new T cell receptor bispecific fusion protein and the first approved treatment option for human leucocyte antigen-A*02:01 (HLA-A*02:01) metastatic uveal melanoma, with a proven benefit in overall survival versus the investigator’s choice. As a first-in-class therapeutic option, this Immune mobilising monoclonal T cell receptor Against Cancer (ImmTAC) is associated with a new adverse event (AE) profile. Based on clinical experience, a national expert group discussed recommendations for tebentafusp treatment, focusing on AE management. Further topics included prerequisites for initiating tebentafusp treatment, appropriate treatment setting, and patient selection criteria. To provide guidance for treating physicians, the resulting recommendations are summarised including a model standard operating procedure for AE management. Patients in good clinical condition and with a low tumour burden are good candidates for tebentafusp treatment, particularly if treated as early as possible after the diagnosis of metastatic disease. The safety profile of tebentafusp is manageable and includes two major pathologies: cytokine release syndrome (CRS) and skin-related events. Postdose monitoring should thus focus on pyrexia and hypotension as the first symptoms of cytokine release. To minimise the risk of hypotension associated with CRS, patients should receive intravenous fluids before starting treatment. The monitoring of liver values is crucial, as patients may experience an increase in transaminases, which can even manifest as tumour lysis syndrome.

Non-alcoholic fatty liver disease in hemochromatosis probands with iron overload and HFE p.C282Y/p.C282Y

BackgroundThe aim of this study was to identify characteristics of non-alcoholic fatty liver disease (NAFLD) in adults with HFE p.C282Y/p.C282Y.MethodsWe retrospectively studied non-Hispanic white hemochromatosis probands with iron overload (serum ferritin (SF) > 300 µg/L (M), > 200 µg/L (F)) and p.C282Y/p.C282Y at non-screening diagnosis who did not report alcohol consumption > 14 g/d, have cirrhosis or other non-NAFLD liver disorders, use steatogenic medication, or have diagnoses of heritable disorders that increase NAFLD risk. We identified NAFLD-associated characteristics using univariate and multivariable analyses.ResultsThere were 66 probands (31 men, 35 women), mean age 49 ± 14 (SD) y, of whom 16 (24.2%) had NAFLD. The following characteristics were higher in probands with NAFLD: median SF (1118 µg/L (range 259, 2663) vs. 567 µg/L (247, 2385); p = 0.0192); prevalence of elevated ALT/AST (alanine/aspartate aminotransferase) (43.8% vs. 10.0%; p = 0.0056); and prevalence of type 2 diabetes (T2DM) (31.3% vs. 10.0%; p = 0.0427). Mean age, sex, and prevalences of human leukocyte antigen-A*03 positivity, body mass index ≥ 30.0 kg/m2, hyperlipidemia, hypertension, and metabolic syndrome in probands with/without NAFLD did not differ significantly. Logistic regression on NAFLD using variables SF, elevated ALT/AST, and T2DM revealed: SF (p = 0.0318; odds ratio 1.0–1.0) and T2DM (p = 0.0342; 1.1–22.3). Median iron removed to achieve iron depletion (QFe) in probands with/without NAFLD did not differ significantly (3.6 g (1.4–7.2 g) vs. 2.8 g (0.7–11.0 g), respectively; p = 0.6862).ConclusionsNAFLD in hemochromatosis probands with p.C282Y/p.C282Y is associated with higher median SF and greater T2DM prevalence, after adjustment for other factors. NAFLD does not influence QFe significantly.

Tebentafusp: a first-in-class treatment for metastatic uveal melanoma.

Tebentafusp is a first-in-class immunotherapy agent that comprises an engineered T-cell receptor targeting a gp100 epitope presented by human leukocyte antigen-A*02:01 cells, fused to an anti-CD3 single-chain variable fragment. Tebentafusp is both the first bispecific T-cell engager to show efficacy in the treatment of advanced solid cancer and the first anti-cancer treatment to demonstrate an overall survival benefit in patients with uveal melanoma (UM). This review article will focus on the clinical development of tebentafusp, the mechanism of action and resultant evolution of the management of advanced UM.

Simultaneous loading of PCR-based multiple fragments on mouse artificial chromosome vectors in DT40 cell for gene delivery

Homology-directed repair-mediated knock-in (HDR-KI) in combination with CRISPR-Cas9-mediated double strand break (DSB) leads to high frequency of site-specific HDR-KI. While this characteristic is advantageous for generating genetically modified cellular and animal models, HDR-KI efficiency in mammalian cells remains low. Since avian DT40 cells offer distinct advantage of high HDR-KI efficiency, we expanded this practicality to adapt to mammalian research through sequential insertion of target sequences into mouse/human artificial chromosome vector (MAC/HAC). Here, we developed the simultaneous insertion of multiple fragments by HDR method termed the simHDR wherein a target sequence and selection markers could be loaded onto MAC simultaneously. Additionally, preparing each HDR donor containing homology arm by PCR could bypass the cloning steps of target sequence and selection markers. To confirm the functionality of the loaded HDR donors, we constructed a MAC with human leukocyte antigen A (HLA-A) gene in the DT40 cells, and verified the expression of this genomic region by reverse transcription PCR (RT-PCR) and western blotting. Collectively, the simHDR offers a rapid and convenient approach to generate genetically modified models for investigating gene functions, as well as understanding disease mechanisms and therapeutic interventions.

Identification of novel interferon responsive protein partners of human leukocyte antigen A (HLA-A) using cross-linking mass spectrometry (CLMS) approach

The interferon signalling system elicits a robust cytokine response against a wide range of environmental pathogenic and internal pathological signals, leading to induction of a subset of interferon-induced proteins. We applied DSS (disuccinimidyl suberate) mediated cross-linking mass spectrometry (CLMS) to capture novel protein–protein interactions within the realm of interferon induced proteins. In addition to the expected interferon-induced proteins, we identified novel inter- and intra-molecular cross-linked adducts for the canonical interferon induced proteins, such as MX1, USP18, OAS3, and STAT1. We focused on orthogonal validation of a cohort of novel interferon-induced protein networks formed by the HLA-A protein (H2BFS-HLA-A-HMGA1) using co-immunoprecipitation assay, and further investigated them by molecular dynamics simulation. Conformational dynamics of the simulated protein complexes revealed several interaction sites that mirrored the interactions identified in the CLMS findings. Together, we showcase a proof-of-principle CLMS study to identify novel interferon-induced signaling complexes and anticipate broader use of CLMS to identify novel protein interaction dynamics within the tumour microenvironment.

Molecular Characterization of MHC Class I Alpha 1 and 2 Domains in Asian Seabass (Lates calcarifer).

The Asian seabass is of importance both as a farmed and wild animal. With the emergence of infectious diseases, there is a need to understand and characterize the immune system. In humans, the highly polymorphic MHC class I (MHC-I) molecules play an important role in antigen presentation for the adaptive immune system. In the present study, we characterized a single MHC-I gene in Asian seabass (Lates calcarifer) by amplifying and sequencing the MHC-I alpha 1 and alpha 2 domains, followed by multi-sequence alignment analyses. The results indicated that the Asian seabass MHC-I α1 and α2 domain sequences showed an overall similarity within Asian seabass and retained the majority of the conserved binding residues of human leukocyte antigen-A2 (HLA-A2). Phylogenetic tree analysis revealed that the sequences belonged to the U lineage. Mapping the conserved binding residue positions on human HLA-A2 and grass carp crystal structure showed a high degree of similarity. In conclusion, the availability of MHC-I α1 and α2 sequences enhances the quality of MHC class I genetic information in Asian seabass, providing new tools to analyze fish immune responses to pathogen infections, and will be applicable in the study of the phylogeny and the evolution of antigen-specific receptors.

Development of a T Cell-Based COVID-19 Vaccine Using a Live Attenuated Influenza Vaccine Viral Vector

The COVID-19 pandemic emerged in 2020 and has caused an unprecedented burden to all countries in the world. SARS-CoV-2 continues to circulate and antigenically evolve, enabling multiple reinfections. To address the issue of the virus antigenic variability, T cell-based vaccines are being developed, which are directed to more conserved viral epitopes. We used live attenuated influenza vaccine (LAIV) virus vector to generate recombinant influenza viruses expressing various T-cell epitopes of SARS-CoV-2 from either neuraminidase (NA) or non-structural (NS1) genes, via the P2A self-cleavage site. Intranasal immunization of human leukocyte antigen-A*0201 (HLA-A2.1) transgenic mice with these recombinant viruses did not result in significant SARS-CoV-2-specific T-cell responses, due to the immunodominance of NP366 influenza T-cell epitope. However, side-by-side stimulation of peripheral blood mononuclear cells (PBMCs) of COVID-19 convalescents with recombinant viruses and LAIV vector demonstrated activation of memory T cells in samples stimulated with LAIV/SARS-CoV-2, but not LAIV alone. Hamsters immunized with a selected LAIV/SARS-CoV-2 prototype were protected against challenge with influenza virus and a high dose of SARS-CoV-2 of Wuhan and Delta lineages, which was confirmed by reduced weight loss, milder clinical symptoms and less pronounced histopathological signs of SARS-CoV-2 infection in the lungs, compared to LAIV- and mock-immunized animals. Overall, LAIV is a promising platform for the development of a bivalent vaccine against influenza and SARS-CoV-2.

Abstract 5665: LILRB2 mediates the immune escape of breast tumor cells by degrading HLA-A

Abstract Breast cancer has now risen to the number one cancer in the world, posing a great threat to human health. LILRB2 (leukocyte immunoglobulinlike receptor B2) is an important immunosuppressive receptor protein, which is mainly expressed in myeloid cells, such as macrophages and dendritic cells. At present, we have found clinically that patients with breast cancer bone and bone marrow metastasis have higher expression of LILRB2. In our research, we used Western blotting, real-time fluorescent quantitative Polymerase Chain Reaction (RT-PCR), flow cytometry, and other experimental methods to explore the expression and function of LILRB2 in breast cancer cells. In our research, we found that LILRB2does increase expression in breast cancer cells, therefore, we want to explore the role of LILRB2 in breast cancer cells. we find that LILRB2 will accelerate the proliferation of tumor cells and increase their migration ability. We tested the related signal pathways and found that LILRB2 can promote the enhancement of the NF-Kb signal pathway. Further, we have done related LILRB2 correlation analysis and found that LILRB2 can reduce human leukocyte antigen-A (HLA-A) Expression. Next, we tested the changes in the level of major histocompatibility complex (MHC-1) related mRNA and found that its mRNA expression increased, which was inconsistent with the decrease in its protein level we observed. Therefore, we used the proteasome inhibitor MG132 for treatment, and the results showed after adding MG132, the decrease in HLA-A expression caused by overexpression of LILRB2 was restored. Next, we knocked down the breast cancer cell line of membrane-associated ring finger (MARCH9). After we knocked down MARCH9, transfection of LILRB2 did not increase the ubiquitination of HLA-A. Therefore we show that LILRB2 can mediate the post-translational modification of HLA-A via MARCH9, which in turn mediates the degradation ofHLA-A. In conclusion, our research shows that LILRB2 maybe a candidate of clinical target for the treatment of breast cancer, preventing possible bone and bone marrow metastasis from breast cancer. Citation Format: Hui Zhao, zhiyuan jiang, zhiyu wang, yujie chang, shunyi ruan. LILRB2 mediates the immune escape of breast tumor cells by degrading HLA-A [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 5665.

Regulatory T cells induce a suppressive immune milieu and promote lymph node metastasis in intrahepatic cholangiocarcinoma

BackgroundEmerging evidence indicates that immunogenicity plays an important role in intrahepatic cholangiocarcinoma (ICC). Herein, we systematically evaluated the clinical relevance of immunogenicity in ICC.MethodsHighly immunogenic ICCs identified in the public dataset and the Cancer Immunome Atlas (TCIA) were assessed to determine the prognostic impact of immunogenicity in ICC and key components after curative resection. We also investigated the clinical relevance of the immune milieu in ICC.ResultsUsing the Gene Expression Omnibus dataset 89749 and TCIA, we identified CD8+/forkhead box P3 (FoxP3)+ tumour-infiltrating lymphocytes (TILs), T-cell immunoglobulin and mucin domain 3 (TIM-3) and human leukocyte antigen-A (HLA-A) in highly immunogenic ICCs. Immunohistochemical analysis of the in-house cohort showed that intratumoral FoxP3+ TILs correlated with CD8+ TILs (P = 0.045, Fisher’s exact test) and that high FoxP3+/CD8+ ratio (FCR) was an important marker for poor survival (P < 0.001, log-rank test). Furthermore, the FCR was higher in tumour-free lymph nodes in ICCs with lymph node metastases than in those without lymph node metastases (P = 0.003, Mann–Whitney U test).ConclusionsFCR should be considered an important biomarker that represents the immune environment of ICC based on its potentially important role in tumour progression, especially lymph node metastasis.

Human Leukocyte Antigen-A, B, and DRB1 Diversity in Renal Transplant Patients and Donors

Background: The understanding of transplant acceptance or rejection derives directly from knowing human leukocyte antigen (HLA) involved in the immune response. The HLA of the major histocompatibility complex contains a numerous family of genes located on the short arm of the chromosome number 6 and divided majorly into two classes, Class I (HLA-A, B, and C) and Class II (HLA-DR, DQ, and DP). The detection and detailed information of these histocompatibility genes are essential for the better outcome of organ transplants. Aims and Objectives: The aim of the present study is to analyze the frequencies of HLA-A, B, and DRB1 in chronic kidney disease (CKD) patients and their prospective donors as well as to see the prevalence of heterogenicity. Materials and Methods: A total of 264 patients diagnosed with CKD and 333 potential donors were studied retrospectively in the present study. All these cases were analyzed for HLA-A, B, and DRB1 loci typing by PCR-SSOP method based on the Luminex platform. Results: We identified 15 different alleles of HLA-A, 29 of HLA-B, and 13 of HLA-DRB1 amongst studied samples. Out of these identified HLA alleles, HLA-A*02, HLA-B*35, and HLA-DRB1*15 were more frequent as compared to others. The results showed significant heterogenicity in the identified HLA-A, B, and DRB1alleles. Conclusion: The result highlights the diversity of HLA-A, B, and DRB1 alleles and is valuable as a reference for organ transplantations. Further, these findings can also guide in better donor selection and hence improved transplant outcome. In addition, this information could be a starting point for the development of an indigenous transplant assay kit.

Addressing beta‐lactam allergy: A time for action

Addressing beta‐lactam allergy: A time for action

COVID-19 mRNA vaccine safety during the first 6 months of roll-out in the USA

COVID-19 mRNA vaccine safety during the first 6 months of roll-out in the USA

WT1 epitope-specific IgG and IgM antibodies for immune-monitoring in patients with advanced sarcoma treated with a WT1 peptide cancer vaccine.

The Wilms' tumor gene WT1 is highly expressed in various malignancies and may be a common target antigen for cancer immunotherapy. In our group, peptide-based cancer vaccines targeting WT1 CTL epitopes were developed as an immunotherapy for these malignancies. In the present study, WT1 epitope-specific immune responses were analyzed in 31 patients with advanced sarcoma with human leukocyte antigen-A*24:02- and WT1-expressing tumors who received the WT1-235 peptide vaccine as monotherapy. The serum levels of IgG and IgM antibodies against the target epitope WT1-235 and the non-target epitopes WT1-332 and WT1-271 were measured using ELISA. IgM antibodies against WT1-235, WT1-332 and WT1-271 were detected in three (9.6%), four (12.9%) and 20 patients (64.5%), respectively, prior to vaccine administration, indicating immune recognition of the WT1 antigen prior to administering the vaccine. Of 15 patients who had completed the 3-month treatment protocol, WT1-235 IgG was positive in five (33.3%) patients. An enzyme-linked immunospot assay revealed that WT1-235 epitope-specific IL-10 production/secretion in peripheral blood mononuclear cells declined in the first month of vaccine administration in all three patients with positivity for WT1-235 IgM at the start of the vaccine. Furthermore, positivity for both WT1-235 and WT1-271 IgM antibodies at the start of treatment was associated with unfavorable tumor control at 3 months after vaccine administration. These results suggested that WT1 epitope-specific IgG and IgM antibodies may be utilized as immune-monitoring markers for WT1 peptide cancer vaccine immunotherapy. The trials were entered in the University hospital Medical Information Network (UMIN) Clinical Trials Registry (https://www.umin.ac.jp/ctr; no. UMIN000002001 on May 24, 2009 and no. UMIN000015997 on December 20, 2014).

A COVID-19 T-Cell Response Detection Method Based on a Newly Identified Human CD8+ T Cell Epitope from SARS-CoV-2 - Hubei Province, China, 2021.

IntroductionSimilar to antibody detection, severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2)-specific T-cell response evaluation is also pivotal among the coronavirus disease 2019 (COVID-19) convalescents and the vaccinated populations. Nucleocapsid (N) protein is one of the main structural proteins of SARS-CoV-2 and can trigger T-cell responses in humans.MethodsAn overlapping peptide pool covering the full length of the N protein was designed, peptides with positive T-cell activating potency in COVID-19 convalescents were screened, and CD8+ T cell epitopes were further identified. The epitope was used to detect the SARS-CoV-2-specific CD8+ T cell responses in COVID-19 convalescents based in intracellular cytokine staining and tetramer staining in flow cytometry. ResultsA human leukocyte antigen A (HLA-A)*1101-restricted CD8+ T cell epitope, which could stimulate the production of IFN-γ via peripheral blood mononuclear cells (PBMCs) of the convalescents was defined, and the tetramer generated with this epitope could detect SARS-CoV-2-specific T cells in the PBMCs of the convalescents. The structural investigation eliminated that the epitope was a typical HLA-A*1101-restricted T-cell epitope which was conserved among all the sarbecoviruses. DiscussionThe newly identified SARS-CoV-2-derived T-cell epitope was helpful to detect the cellular immunity against different sarbecoviruses including SARS-CoV and SARS-CoV-2. This study provided an evaluation method and also a peptide candidate for the research and development of T-cell based vaccine for the virus.