Isolation and rapid identification of an abundant self-peptide from class IIHLA-DRB1*0401 alleles induced by measles vaccine virus infection

Class II HLA-DR genes play an important role in the immune response to vira l antigens. The effect of measles vaccine virus (MW) infection on the induc tion of self-peptides presented by HLA-DR molecules during the immune respo nse to viral infection is poorly known. Here, we describe a strategy for is olation and rapid sequence determination of an MW-inducible class II bound peptide from a membrane protein (Leu-13). Peptides bound to HLA-DR4 (DRB1*0 401 peptide complex) were eluted from immunoaffinity-purified HLA-DR4, pept ides were differentially screened by MALDI-TOF-MS and subsequently sequence d by post source decay (PSD)-MALDI-TOF-MS. Human B-cells infected with MVV demonstrated an enhanced pattern of self-peptide production after MVV infec tion. This relatively simple analytical protocol provides a sensitive metho d for the direct identification of peptides associated with MHC class II DR molecules. More broadly, this same approach can be used to identify sequen ces of specific MW processed peptides presented by any class II MHC DR mole cule. (C) 2000 Elsevier Science B.V. All rights reserved.