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Immunodominant MHC-II (Major Histocompatibility Complex II) Restricted Epitopes in Human Apolipoprotein B
- Source :
- Circulation research, vol 131, iss 3
- Publication Year :
- 2022
- Publisher :
- Ovid Technologies (Wolters Kluwer Health), 2022.
-
Abstract
- Background: CD (cluster of differentiation) 4 + T-cell responses to APOB (apolipoprotein B) are well characterized in atherosclerotic mice and detectable in humans. CD4 + T cells recognize antigenic peptides displayed on highly polymorphic HLA (human leukocyte antigen)-II. Immunogenicity of individual APOB peptides is largely unknown in humans. Only 1 HLA-II-restricted epitope was validated using the DRB1*07:01-APOB 3036 –3050 tetramer. We hypothesized that human APOB may contain discrete immunodominant CD4 + T-cell epitopes that trigger atherosclerosis-related autoimmune responses in donors with diverse HLA alleles. Methods: We selected 20 APOB-derived peptides (APOB 20 ) from an in silico screen and experimentally validated binding to the most commonly occurring human HLA-II alleles. We optimized a restimulation-based workflow to evaluate antigenicity of multiple candidate peptides in HLA-typed donors. This included activation-induced marker assay, intracellular cytokine staining, IFNγ (interferon gamma) enzyme–linked immunospot and cytometric bead array. High-throughput sequencing revealed TCR (T-cell receptor) clonalities of APOB-reactive CD4 + T cells. Results: Using stringent positive, negative, and crossover stimulation controls, we confirmed specificity of expansion-based protocols to detect CD4 + T cytokine responses to the APOB 20 pool. Ex vivo assessment of AIM + CD4 + T cells revealed a statistically significant autoimmune response to APOB 20 but not to a ubiquitously expressed negative control protein, actin. Resolution of CD4 + T responses to the level of individual peptides using IFNγ enzyme–linked immunospot led to the discovery of 6 immunodominant epitopes (APOB 6 ) that triggered robust CD4 + T activation in most donors. APOB 6 -specific responding CD4 + T cells were enriched in unique expanded TCR clonotypes and preferentially expressed memory markers. Cytometric bead array analysis detected APOB 6 -induced secretion of both proinflammatory and regulatory cytokines. In clinical samples from patients with angiographically verified coronary artery disease, APOB 6 stimulation induced higher activation and memory phenotypes and augmented secretion of proinflammatory cytokines TNF (tumor necrosis factor) and IFNγ, compared with patients with low coronary artery disease. Conclusions: Using 3 cohorts, each with ≈20 donors, we discovered and validated 6 immunodominant, HLA-II–restricted APOB epitopes. The immune response to these APOB epitopes correlated with coronary artery disease severity.
- Subjects :
- CD4-Positive T-Lymphocytes
workflow
Physiology
Clinical Sciences
Epitopes, T-Lymphocyte
Coronary Artery Disease
Cardiorespiratory Medicine and Haematology
Cardiovascular
Autoimmune Disease
Major Histocompatibility Complex
Epitopes
Interferon-gamma
Mice
Clinical Research
Genetics
2.1 Biological and endogenous factors
Animals
Humans
Aetiology
Apolipoproteins B
Inflammatory and immune system
autoimmunity
Atherosclerosis
T-Lymphocyte
Cardiovascular System & Hematology
alleles
peptides
Peptides
Cardiology and Cardiovascular Medicine
Biotechnology
Subjects
Details
- ISSN :
- 15244571 and 00097330
- Volume :
- 131
- Database :
- OpenAIRE
- Journal :
- Circulation Research
- Accession number :
- edsair.doi.dedup.....ba3a2f2bcd2f6f6e5b919bd461821d9c