Differential amino-terminal anchors for peptide binding to H-2M3a or H-2Kb and H-2Db
Shawar, S.M.; Vyas, J.M.; Shen, E.; Rodgers, J.R.; Rich, R.R.
Journal of Immunology 151(1): 201-210
1993
ISSN/ISBN: 0022-1767 PMID: 7686932 Document Number: 422420
We previously established that H-2M3-a, the H chain of the maternally transmitted Ag (Mta), is specialized for presentation of N-formylated peptides. We hypothesized that the N-formyl group might prevent or limit the presentation of peptide Ag by H-2K and H-2D molecules. We now show by Mta- and OVA-specific CTL assays, peptide competition, and immunofluorescence analyses that N-formyl modification of four antigenic peptides inhibited their binding by either H-2K-b (OVA-Met258-264, VSVNP-52-59, and SVNP-324-332) or H2-D-b (SVNP-324-332, and IVNP-366-374). In contrast, N-formyl-OVA-Met258-264 did bind to H2-M3-a. The data imply lack of an N-formyl-binding pocket in classical MHC class I molecules and are consistent with a specialized role for H2-M3-a in presentation of N-formylated peptides such as derived from intracellular prokaryotic parasites.