Inhibited MHC Class I and MHC Class II antigen processing and presentation upon Sars-CoV-2 infection

Abstract Major histocompatibility (MHC) bound viral peptides are the immune signatures to initiate selective and cross-reactive T cell responses. Identifying antigenic targets of adaptive immunity SARS-CoV-2 is a key towards understanding pathogenesis Sars-CoV-2 rapidly evolving mutants. We isolated immunopeptidomes identify naturally processed presented MHC-II (HLA-DR, HLA-DP) MHC-I (HLA-ABC) canonical out-of-frame peptides. identified 5 HLA-DR epitopes (13 peptides) from spike protein, 2 HLA-DP (4 membrane proteins, 1 MHC-Class I different ORF proteins. The were in lower abundances as compared host obscuring identification MHC Some these shown recall responses COVID-19 donors other reported studies. observed downregulation surface total HLA-ABC, expression upon infection possibly restricting presentation therefore delaying response. mechanisms by which evades mediated studied detail groups. Hence, we further investigating modulators pathway using proteomics-based approach. significant CD74 CIITA protein cathepsins infected cells affecting processing These results may help significantly altered antigen cells.