Influence Of MHC Class Research Articles

Abstract 1385: The influence of MHC class I and II on T cell responses in mouse melanoma

Abstract Introduction: Using an in situ vaccine (ISV) regimen consisting of radiation combined with immunocytokine (tumor-targeting mAb linked to IL2), we can cure mice of well established B78 melanoma tumors (B78s). Mice cured of their B78s with ISV demonstrate long-term immune memory, evidenced by rejection of engraftment of a tumor rechallenge >180 days post initial cure of tumor. Traditionally, immaune memory is thought to be mediated via CD8+ T cells, which require antigen presentation via MHC Class I (MHCI). However, B78s express little to no MHCI but do express MHCII when stimulated with IFNγ. While not commonly expressed on solid tumors, MHCII is expressed on 50-60% of melanomas in humans. Here we explored implications of MHCI and MHCII expression in both the primary and long-term memory anti-tumor responses generated with ISV. Methods: CD4+ or CD8+ T cells were depleted in mice during the primary anti-tumor response (i.e. B78 tumor bearing mice receiving the ISV regimen) or during tumor rechallenge experiments (i.e. B78-cured mice rechallenged with B78s). Tumor growth was monitored. In separate studies, tumors and tumor draining lymphnodes (TDLNs) were harvested during the primary antitumor response and analyzed via flow cytometry to assess T cell activation and immune infiltrate. Finally, TDLNs were harvested from B78-cured mice, 7 days after tumor rechallenge, to define memory T cell subsets. Results: Depletion studies revealed CD4+ T cells are required for both the antitumor response to ISV and the long-term memory response in B78-cured mice, but CD8+ T cells are not required for either of these responses. Increased CD8+ and CD4+ T cell infiltrates are observed in the tumor microenvironment during the primary anti-tumor response. In B78-cured mice, though not required for memory responses, CD8+ central memory T cells are significantly increased in the TDLNs compared to naïve or primary tumor bearing mice. The amount of CD4+ effector memory T cells are significantly increased in the TDLN of B78-cured mice compared to CD8+ effector memory T cells. Conclusion: Often not expressed on solid tumors, MHCII is expressed on some melanoma tumors, and its expression has been correlated with a positive response to immunotherapies. CD4+ cytotoxic T cells can directly engage MHCII on tumors, suggesting this interaction has an important role in the response to immunotherapy for MHCII expressing tumors. Our data suggest that CD4+ T cells drive both the primary anti-tumor and long-term immune memory responses in the B78 model when treating with this effective ISV. We are continuing our efforts to understand the characteristics of the B78 cell line that may be relevant to its response to immunotherapy and its resistance to single agent checkpoint blockade. Understanding the cellular and molecular mechanisms involved in ISV-induced immune recognition and destruction of B78s may guide future improvements of this clinically-relevant immunotherapy regimen. Citation Format: Amy K. Erbe, Arika Feils, Mackenzie Heck, Sabrina VandenHeuvel, Julianna Castillo, Alina Hampton, Lizzie Frankel, Anna Hoefges, Peter Carlson, Alex A. Pieper, Taylor Aiken, Lauren Zebertavage, David Komjathy, Dan Spiegelman, Noah Tsarovsky, Zachary S. Morris, Ravi Patel, Alexander Rakhmilevich, Paul M. Sondel. The influence of MHC class I and II on T cell responses in mouse melanoma [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 1385.

Influence of MHC Class I Chain-Related Gene Α (MICA) Polymorphisms on Cytomegalovirus Infection after Allogeneic Hematopoietic Cell Transplantation

BackgroundCytomegalovirus (CMV) is a common infectious complication after allogeneic hematopoietic cell transplantation (alloHCT). Efforts to enhance immune reconstitution post-transplant have been pursued to help facilitate clearance of such infections. Assessment of natural killer (NK) cell allo-reactivity with investigation of killer cell immunoglobulin-like receptors has been reported to be associated with protection from CMV infection after alloHCT (Davis ZB et al, BBMT 2015). In addition, the activating NKG2D receptor controls immune responses by regulating NK cells, NKT cells and γδ-T cells. MHC class I chain-related gene A (MICA) is a polymorphic ligand of the NKG2D receptor on these immune effector cells. Given the potential benefit of NK cell allo-reactivity for protection from CMV infection after alloHCT we hypothesized that MICA polymorphisms may influence CMV infection rates after such transplants.MethodsWe conducted a single center, retrospective analysis of allogeneic HCTs for adults with hematologic malignancies in which MICA data were available for donors and recipients. Analysis was restricted to patients with T-cell replete HLA-8/8 matched related or unrelated donor. Fine and Gray regression was used to identify risk factors for CMV infection. The first episode of graft-versus-host-disease (GVHD) was analyzed relative to CMV as a time-dependent covariate. An analysis was performed examining dimorphisms at the MICA-129 position, which previously has been categorized as weaker (valine/valine: V/V), heterozygous (methionine/valine: M/V), or stronger (methionine/methionine: M/M) receptor binding affinity.ResultsFrom 2000-2016, 423 alloHCT patients were identified who had MICA data. Diagnoses included 197 AML, 82 MDS, 34 ALL, 34 NHL, 22 CML, 12 CMML, 9 CLL, 9 myelofibrosis, 9 plasma cell myeloma, 9 other leukemias, and 6 Hodgkin lymphoma. High, intermediate, and low co-morbidity index was seen in 42%, 33%, and 25% of patients, respectively. Median age at transplant was 52 years (range, 18-76), with 95% Caucasian. A myeloablative transplant was performed in 80% of patients and 52% had a bone marrow graft source. CMV infection occurred in 141 (33%) of patients at a median time of 46 days post-transplant (range, 0-609 days) with 29 (21%) occurring within 30 days, 108 (77%) within 100 days and 33 (23%) after day 100. Thirty-three (8%) patients were MICA mismatched with their donor. Donor MICA-129 dimorphisms included 203 (48%) V/V, 190 (45%) M/V and 30 (7%) M/M. Baseline donor(d)/recipient(r) CMV serostatus for V/V vs. M/V + M/M cohorts were 25% vs. 28% for d+/r+, 11% vs 9% for d+/r-, 39% vs. 37% for d-/r+, and 25% vs. 26% for d-/r- (P=0.75). In univariate analysis, MICA mismatch was associated with a higher risk of CMV (HR 1.64, CI 1.00-2.69, P=0.049), and V/V donor MICA-129 dimorphism with a marginally higher risk of CMV (HR 1.32, CI 0.85-1.83, P=0.10). In multivariable analysis, MICA mismatch was not associated with CMV infection (HR 1.38, CI 0.83-2.29, P=0.22) while V/V donor MICA-129 dimorphism was associated (HR 1.40, CI 1.00-1.96, P=0.05) (Figure 1). Other significant variables in multivariable analysis were year of transplant (HR 0.95, CI 0.92-0.99 P=0.01), non-Caucasian race (HR 2.15, CI 1.18-3.91, P=0.01), high-risk disease (HR 1.62, CI 1.13-2.32 P=0.008), baseline CMV serostatus (HR 7.51, CI 3.76-15.0, P<0.001 for d+/r+, HR 7.73, CI 3.90-15.3, P<0.001 for d-/r+, both relative to d-/r-), and development of GVHD prior to CMV (HR 2.02, CI 1.37-2.96, P<0.001). There was no association of MICA mismatch with acute (HR 1.05, CI 0.66-1.68, P=0.83) or chronic (HR 0.94, CI 0.51-1.76, P=0.85) GVHD. As compared to the V/M+M/M cohort, patients with V/V donors had a longer interval from diagnosis to transplant (median 8.2 vs 6.2 months, P=0.036) and more often received myeloablative conditioning (P=0.030).ConclusionWe conclude that the donor MICA-129 V/V dimorphism with weak NKG2D receptor binding affinity is associated with increased risk of CMV infection after alloHCT. The presence of at least one M residue encoding allele may confer enhanced NK cell anti-viral reactivity. These observations potentially may have implications in optimizing donor selection. Further investigation of MICA may also help better predict which patients are at higher risk of CMV infection in order to consider intervening sooner with CMV specific therapy or more rapid tapering of immunosuppression. [Display omitted] DisclosuresGerds:CTI BioPharma: Consultancy; Incyte: Consultancy. Majhail:Sanofi: Honoraria; Anthem, Inc.: Consultancy.

Cattle NK Cell Heterogeneity and the Influence of MHC Class I.

Primate and rodent NK cells form highly heterogeneous lymphocyte populations owing to the differential expression of germline-encoded receptors. Many of these receptors are polymorphic and recognize equally polymorphic determinants of MHC class I. This diversity can lead to individuals carrying NK cells with different specificities. Cattle have an unusually diverse repertoire of NK cell receptor genes predicted to encode receptors that recognize MHC class I. To begin to examine whether this genetic diversity leads to a diverse NK cell population, we isolated peripheral NK cells from cattle with different MHC homozygous genotypes. Cytokine stimulation differentially influenced the transcription of five receptors at the cell population level. Using dilution cultures, we found that a further seven receptors were differentially transcribed, including five predicted to recognize MHC class I. Moreover, there was a statistically significant reduction in killer cell lectin-like receptor mRNA expression between cultures with different CD2 phenotypes and from animals with different MHC class I haplotypes. This finding confirms that cattle NK cells are a heterogeneous population and reveals that the receptors creating this diversity are influenced by the MHC. The importance of this heterogeneity will become clear as we learn more about the role of NK cells in cattle disease resistance and vaccination.

Macaque species susceptibility to simian immunodeficiency virus: increased incidence of SIV central nervous system disease in pigtailed macaques versus rhesus macaques.

Immune pressure exerted by MHC class I-restricted cytotoxic T cells drives the development of viral escape mutations, thereby regulating HIV disease progression. Nonetheless, the relationship between host immunity and HIV central nervous system (CNS) disease remains poorly understood. The simian immunodeficiency virus (SIV) macaque model recapitulates key features of HIV infection including development of AIDS and CNS disease. To investigate cell-mediated immunity regulating SIV CNS disease progression, we compared the incidence of SIV encephalitis and the influence of MHC class I allele expression on the development of CNS disease in rhesus macaques (Macaca mulatta) versus pigtailed macaques (Macaca nemestrina). After inoculation with the immunosuppressive swarm SIV/DeltaB670 and the neurovirulent molecular clone SIV/17E-Fr, pigtailed macaques progressed more rapidly to AIDS, had higher plasma and cerebrospinal fluid (CSF) viral loads, and were more likely to progress to SIV-associated encephalitis (SIVE) compared to rhesus macaques. In addition, MHC class I alleles were neuroprotective in both species (Mamu-A*001 in rhesus macaques and Mane-A1*084:01:01 in pigtailed macaques); animals expressing these alleles were less likely to develop SIV encephalitis and correspondingly had lower viral replication in the brain. Species-specific differences in susceptibility to SIV disease demonstrated that cell mediated immune responses are critical to SIV CNS disease progression.

The role of MHC class I and class II molecules in susceptibility to Lyme disease in inbred B10 H-2 congenic and recombinant mice

We have further developed the mouse model of Lyme disease using B10 H-2 congenic and recombinant strains. The influence of MHC class I and class II genes of the mouse H-2 complex on the susceptibility and/or resistance to Lyme disease was studied. We report that B10 strains congenic to the haplotypes, H-2k, H-2d, H-2f, H-2q, and H-2b are highly susceptible to Lyme disease as they develop high antibody titers and severe disease over mice of other haplotypes used in this study. By using recombinant strains we demonstrate that this susceptibility is genetically based and specifically involves the K and D regions (MHC class I genes) and I-A and I-E regions (MHC class II genes) of the H-2 complex.

128: Influence of MHC Class II Matching on Regulatory Tolerance to Heart Transplants

128: Influence of MHC Class II Matching on Regulatory Tolerance to Heart Transplants

The Influence of MHC Class II Molecules Containing the Rheumatoid Arthritis Shared Epitope on the Immune Response to Aggrecan G1 and Its Peptides

Aggrecan has been implied as an autoantigen in rheumatoid arthritis (RA). Immunization with aggrecan induces arthritis in BALB/c (H-2(d)) mice but not in other strains of mice [e.g. C57BL/6 (H-2(b))]. In humans, the strongest genetic association with RA is to the shared epitope (SE), and aggrecan peptides are predicted to bind to the SE. Therefore, we hypothesized that C57BL/6 mice transgenic (tg) for the RA SE (DR4 tg mice) may be susceptible to aggrecan-induced arthritis. C57BL/6 and DR4 tg mice were immunized with a mixture of SE-binding aggrecan peptides and tested for immune responses to the corresponding peptides as well as aggrecan. Sustained T- and B-cell immune responses to aggrecan and several of its peptides were detected in DR4 tg mice. C57BL/6 mice showed only transient T-cell responses to different immunizing peptides and little B-cell response. Therefore, an immune response to peptides of aggrecan can be induced experimentally in DR4 tg mice as anticipated from the predicted and actual binding affinities of these peptides for the RA SE. Failure to induce arthritis in these DR4 tg mice may be due to a lack of appropriate non-MHC genes.

Molecular and cellular evidence for T-cell stimulation by allogeneic retinal pigment epithelium cells in vitro.

The rejection of retinal pigment epithelium (RPE) allografts is a major barrier to long-term success after retinal transplantation. The aim of this study was to investigate the action of RPE cells on allogeneic T cells in coculture with or without macrophages. For the detection of T-cell activation the interleukins IL-1beta and IL-2, typical for this process, were investigated. Human RPE cells (6 x 10(5) cells/flask) were used as stimulator cells. To investigate the influence of MHC class II molecules the RPE cells were pre-incubated with different concentrations of interferon-gamma (IFN-gamma; 0, 50, 100, or 250 U/ml) for 4 days. This was followed by coculture with either 6 x 10(6) T cells or, in a second trial, the T cells plus 6 x 10(5) macrophages. The mRNAs of the cytokines under study were detected using a reverse-transcriptase polymerase chain reaction and were quantified by colorimetry after 6 h. The cytokine protein content in the supernatants was measured after 20 h using specific enzyme-linked immunoabsorbent assays. Cytokine-specific mRNAs and proteins were found in all samples. After coculture the level of IL-1beta mRNA was higher and that of cytokine-specific protein was significantly increased. Furthermore, the addition of macrophages led to increased cytokine secretion but a general influence of the pre-activation with interferon could not be found. Similar results were detected for IL-2; at the highest dose, IFN-gamma preactivation and, in combination with macrophages, a significant increase in the protein level could be found. These results show that RPE cells are able to activate allogeneic T cells in vitro. Professional antigen-presenting cells may promote this process, as may pre-treatment with IFN-gamma. The circumstances modelled here are involved in the rejection process after RPE transplantation in humans and help to explain this immune response.

Differential recognition of MHC class I molecules of xeno-/allo-endothelial cells by human NK cells

Using human umbilical vein endothelial cells (HUVEC) and porcine aortic endothelial cells (PAEC) as target cells, human peripheral blood NK cells (PBNK) and NK92 cells as effector cells, the differential cytotoxicities of NK cells to allo- and xeno-endothelial cells were studied. The influence of MHC class I molecules on the cytotoxicity of human NK cells was assayed using acid treatment, and blockades of MHC class I antigens, CD94 and KIR (NKB1). The results indicated that the killing of PAEC by the two kinds of NK cells is higher than that of HUVEC. After acid treatment, the cytotoxicity of the two kinds of NK cells to PAEC and HUVEC is significantly enhanced, but the magnitude of the enhancement is different. The enhancement of NK killing to acid treated HUVEC is much greater than that to PAEC. Blockade of CD94 mAb did not alter the NK cytotoxicity, while blockade of NKB1 mAb enhanced the cytotoxicity of PBNK to HUVEC and PAEC by 95% and 29% respectively. The results above suggested that the differential recognition of MHC I molecules of xeno-endothelial cells by human NK cells could be the major reason for higher NK cytotoxicity to PAEC. KIR might be the primary molecule that transduced inhibitory signals when endothelial cells were injured by NK cells.

Influence of MHC class I and class II (mis)matching between donor and recipient on the cytomegalovirus induced accelerated graft arteriosclerosis in a rat aorta transplant model

Influence of MHC class I and class II (mis)matching between donor and recipient on the cytomegalovirus induced accelerated graft arteriosclerosis in a rat aorta transplant model

Influence of MHC class I and class II (mis)matching between donor and recipient on the cytomegalovirus induced accelerated graft arterioscierosis in a rat aorta transplant model

Influence of MHC class I and class II (mis)matching between donor and recipient on the cytomegalovirus induced accelerated graft arterioscierosis in a rat aorta transplant model

The role of MHC class I and class II molecules in susceptibility to Lyme disease in inbred B10 H-2 congenic and recombinant mice

We have further developed the mouse model of Lyme disease using B10 H-2 congenic and recombinant strains. The influence of MHC class I and class II genes of the mouse H-2 complex on the susceptibility and/or resistance to Lyme disease was studied. We report that B10 strains congenic to the haplotypes, H-2k, H-2d, H-2f, H-2q, and H-2b are highly susceptible to Lyme disease as they develop high antibody titers and severe disease over mice of other haplotypes used in this study. By using recombinant strains we demonstrate that this susceptibility is genetically based and specifically involves the K and D regions (MHC class I genes) and I-A and I-E regions (MHC class II genes) of the H-2 complex.

An analysis of α/β TCR V gene expression in the human thymus

We have previously analysed alpha/beta T cell receptor (TCR) V gene usage in CD4+ and CD8+ subpopulations from human peripheral blood lymphocytes (PBL) and umbilical cord blood, and described a biased usage of some of the TCR V beta genes towards the CD4+ subpopulation. In this report, the TCR V gene usage in single positive (SP) CD4+ or CD8+ human thymocytes was analysed. Three previously described mAb with a biased usage in PBL and umbilical cord blood also had a skewed reactivity towards the CD4+ subpopulation in SP human thymocytes. Thus, in all 12 cases V beta 5.1 and V beta 6.7, and in 11/12 cases V beta 12 were preferentially used in the CD4+CD8-, compared to the CD4-CD8+ thymic subpopulation. Altogether, these results suggest a selection process in the thymus, supposedly through the positive influence of MHC class II determinants, to be responsible for this non-random, skewed TCR V gene usage.