372: Leukemic Blasts Acting as Host Antigen Presenting Cells Trigger a Combined CD4 and CD8 Allo-Immune Response Directed against Mismatched HLA Class I

Abstract Previous studies have demonstrated that recipient mice require the production of nitric oxide (NO) within their antigen presenting cells (APC) in order to generate IgG anti-donor immunity against allogeneic platelet transfusions. NO has a complex biochemistry and several of its conjurors could be involved in this response; the most obvious is peroxynitrite (ONOO-) generated by the spontaneous combination of NO and superoxide (O2•−). ONOO- is a potent oxidant that can spontaneously nitrosylate lysine and tyrosine residues in proteins within the phagolysosome. To address the role of ONOO- in platelet immunity, we transfused GP91 PHOX knockout mice that lack the ability to produce O2•− and thus ONOO-. Results show that when wild type C57BL/6 mice were transfused with allogeneic BALB/c platelets, they developed a weak IgG anti-donor antibody response by the fifth transfusion. In contrast, PHOX KO mice generated IgG anti-donor antibodies by the 2nd transfusion and their IgG anti-donor antibody titres were significantly higher than the WT recipients. This suggested that ONOO- and protein nitrosylation may be linked with an immunosuppressive event within the recipient. This was confirmed by demonstrating that in vitro nitrosylation of platelet antigens with the ONOO- donor SIN-1 inhibited the ability of the platelets to mount an IgG immune response when transfused into allogeneic recipients. Nitrosylated platelet antigen trafficking within recipient APC was assessed by using adherent macrophages and various inhibitors of processing. When adherent APC were pulsed with nitrosylated platelet antigens in the presence of either Brefeldin A or proteosome inhibitors, IgG anti-platelet immunity against the platelets was restored. Furthermore, the IgG immunity could also be rescued against the nitrsosylated platelets if the recipients were first depleted of CD8+ T cells by injection of a monoclonal antibody. These results suggest that if platelet antigens are nitrosylated within antigen presenting cells, they are preferentially shunted to the MHC class I processing pathway and presented to CD8+ T cells that suppress the IgG immune response. Thus, it appears that reactive oxygen species act as intracellular regulators that determine whether a productive IgG immune response against platelet transfusions will occur.

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The Interaction of LILRB2 with HLA-B is Associated with Psoriasis Susceptibility

10.1101/741983 ◽

2019 ◽

Author(s):

Rebecca L. Yanovsky ◽

Haoyan Chen ◽

Stephen Leslie ◽

Mary Carrington ◽

Wilson Liao

Keyword(s):

Genome Wide Association Study ◽

Killer Cell ◽

Human Leukocyte ◽

Antigen Presenting Cells ◽

Hla Class I ◽

Class I ◽

Hla Class I Molecules ◽

Genome Wide ◽

Related Group ◽

Antigen Presenting

ABSTRACTGenetic variation within the major histocompatibility complex (MHC) class I is a well-known risk factor for psoriasis. While the mechanisms behind this variation are still being fully elucidated, human leukocyte antigen (HLA) presentation of auto-antigens as well as the interaction of HLA-B with killer cell immunoglobulin-like receptors (KIRs) have been shown to contribute to psoriasis susceptibility. Here we demonstrate that the interaction of HLA class I molecules with leukocyte immunoglobulin-like receptors (LILR), a related group of immunomodulatory receptors primarily found on antigen presenting cells, also contributes to psoriasis susceptibility. We used previously characterized binding capacities of HLA-A, HLA-B, and HLA-C allotypes to two inhibitory LILRs, LILRB1 and LILRB2, to investigate the effect of LILRB1/2 binding in two large genome wide association study cohorts of psoriasis patients and controls (N = 10,069). We found that the strength of binding of LILRB2 to HLA-B was inversely associated with psoriasis risk (p = 2.34E-09, OR [95% CI], 0.41 [0.30−0.55]) independent of individual class I or II allelic effects. We thus propose that weak binding of inhibitory LILRB2 to HLA-B may play a role in patient susceptibility to psoriasis via increased activity of antigen presenting cells.

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Antigen identification for HLA class I– and HLA class II–restricted T cell receptors using cytokine-capturing antigen-presenting cells

Science Immunology ◽

10.1126/sciimmunol.abf4001 ◽

2021 ◽

Vol 6 (55) ◽

pp. eabf4001

Author(s):

Mark N. Lee ◽

Matthew Meyerson

Keyword(s):

T Cell ◽

T Cell Activation ◽

Cell Activation ◽

Human Leukocyte ◽

Antigen Presenting Cells ◽

Hla Class I ◽

Class Ii ◽

Class I ◽

Identification System ◽

Antigen Presenting

A major limitation to understanding the associations of human leukocyte antigen (HLA) and CD8+ and CD4+ T cell receptor (TCR) genes with disease pathophysiology is the technological barrier of identifying which HLA molecules, epitopes, and TCRs form functional complexes. Here, we present a high-throughput epitope identification system that combines capture of T cell–secreted cytokines by barcoded antigen-presenting cells (APCs), cell sorting, and next-generation sequencing to identify class I– and class II–restricted epitopes starting from highly complex peptide-encoding oligonucleotide pools. We engineered APCs to express anti-cytokine antibodies, a library of DNA-encoded peptides, and multiple HLA class I or II molecules. We demonstrate that these engineered APCs link T cell activation–dependent cytokines with the DNA that encodes the presented peptide. We validated this technology by showing that we could select known targets of viral epitope–, neoepitope-, and autoimmune epitope–specific TCRs, starting from mixtures of peptide-encoding oligonucleotides. Then, starting from 10 TCRβ sequences that are found commonly in humans but lack known targets, we identified seven CD8+ or CD4+ TCR-targeted epitopes encoded by the human cytomegalovirus (CMV) genome. These included known epitopes, as well as a class I and a class II CMV epitope that have not been previously described. Thus, our cytokine capture–based assay makes use of a signal secreted by both CD8+ and CD4+ T cells and allows pooled screening of thousands of encoded peptides to enable epitope discovery for orphan TCRs. Our technology may enable identification of HLA-epitope-TCR complexes relevant to disease control, etiology, or treatment.

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Efficient Presentation of Naturally Processed HLA Class I Peptides by Artificial Antigen-Presenting Cells for the Generation of Effective Antitumor Responses

Clinical Cancer Research ◽

10.1158/1078-0432.ccr-05-2791 ◽

2006 ◽

Vol 12 (10) ◽

pp. 2967-2975 ◽

Cited By ~ 30

Author(s):

Naoto Hirano ◽

Marcus O. Butler ◽

Zhinan Xia ◽

Alla Berezovskaya ◽

Andrew P. Murray ◽

...

Keyword(s):

Antigen Presenting Cells ◽

Hla Class I ◽

Class I ◽

Artificial Antigen ◽

Antigen Presenting

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Engineered Antigen- Presenting Cells Expressing Human HLA Class-II DR Alleles Support Efficient Enrichment and Expansion of Antigen Specific Th1 CD4[+] T-Cells Which Are Functionally Augmented by IL-15Rα/IL-15 Complexes

Blood ◽

10.1182/blood.v120.21.1905.1905 ◽

2012 ◽

Vol 120 (21) ◽

pp. 1905-1905

Author(s):

Aisha N. Hasan ◽

Rosanna J. Ricafort ◽

Annamalai Selvakumar ◽

Ekaterina Doubrovina ◽

Isabelle Riviere ◽

...

Keyword(s):

T Cells ◽

Peptide Pool ◽

Antigen Presenting Cells ◽

Hla Class I ◽

Class Ii ◽

Hla Class Ii ◽

Class I ◽

Invariant Chain ◽

Antigen Presenting ◽

Nih 3T3

Abstract Abstract 1905 Previous studies have affirmed the therapeutic efficacy of adoptively transferred antigen specific CD8+ and CD4+ T-cells (TC) against viral infections and tumors. A major challenge in optimizing this approach is to develop strategies to permit generation of CD4+ and long lived CD8+ TC of defined antigen specificity. We previously described a panel of NIH 3T3 based artifical antigen presenting cells (AAPC) for the immediate generation of HLA class-I restricted CMVpp65 specific CD8+ TC. We now describe a panel of NIH 3T3 based AAPC, each transduced to express a shared HLA DRA 0101 alpha chain and one of the following β chains of the human HLA class-II alleles DRB1 0301, 0701, 1501, 0401 and 1101. At least one of these alleles is inherited by 61% and 59% of caucasians and blacks respectively. These AAPCs were also transduced to co-express the human TC costimulatory molecules B7.1, ICAM-1 and LFA-3. Sensitization of TC from seropositive donors in the presence of IL-2 with AAPCs sharing one of these alleles, either loaded with a CMVpp65 peptide pool or transduced to express the CMV pp65 protein, resulted in 33–71 fold expansion of CMVpp65 specific CD4+ TC that exhibited a Th1 cytokine profile, producing TNF-α and IFNγ in response to the same CMVpp65 epitopes. These TC were also cytotoxic against peptide loaded HLA class-II sharing targets. Epitope mapping demonstrated that the HLA DRB1 0301 restricted TC responded to a CMVpp65 epitope known to be presented by this allele QEFFWDANDIY (aa 509–527) and to an unreported epitope DVEEDLTMTRN (aa 245–263). The DRB1 0701 restricted CD4+ TC responded to 4 different epitopes. Two of these also included nonamer peptide sequences previously reported to be presented by HLA class-I alleles; Q IFLEV QAIRE and PQYSEH PTFTS presented by HLA B44, and a third AGILARNLVPM, contained an epitope presented by HLA B0801. The fourth epitope, KYQEFFWDANDIY is known to be also presented by HLA DRB1 0301. The DRB1 1501 restricted CD4+ TC were also responsive to a known class-II epitope LLQTGIHVRVS (aa 37–55) as well as a new epitope LVSQYTPDSTP (aa 53–71). CD4+ TC from 3 donors also responded to CMVpp65 when sensitized with autologous DCs loaded with CMVpp65 peptide pool, and each recognized the same epitopes as TC sensitized with the class-II AAPCs. Supplementation of TC cultures with soluble IL-15Rα/ IL-15 complexes markedly augmented the proportion of IFNg+ CD4+ TC, while increasing concentrations of IL-2 resulted in generation of Th2 type CD4+ TC generating IL-4, IL-5 and IL-2 in response to re-stimulation with CMVpp65 peptides. This system can therefore be harnessed by cytokine modulation to selectively generate CD4+ TC with a Th1, or Th2 cytokine profile. The fact that the class-II AAPC transduced to express the full sequence of CMVpp65 are able to process and present antigenic epitopes on the surface of the expressed HLA class-II allele in the absence of the human invariant chain and HLA-DM suggests that the mouse 3T3 cells contain sufficiently homologous proteins to permit the transfer of processed peptides to human Class-II alleles for presentation. Alternatively, invariant chain independent pathways could permit delivery of certain immunogenic epitopes to the expressed class II HLA alleles. The repertoire of epitopes presented by the Class-II AAPCs with or without the invariant chain is currently under study. Our results suggest that the panel of AAPCs expressing these HLA DRB1 alleles provides a novel and rapid approach for the generation of Th1 CD4+ virus-specific TC of desired HLA class-II restriction for adoptive therapy of CMV disease to foster lasting immunity with co-infused CMVpp65-specific CD8+ TC. Class-II AAPCs used with different concentrations or types of cytokines may also be useful to generate other functional subsets of CD4+ TC to promote tolerance or enhance tumor- specific immunity. Disclosures: No relevant conflicts of interest to declare.

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