Differential amino-terminal anchors for peptide binding to H-2M3a or H-2Kb and H-2Db.
We previously established that H-2M3a, 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-2Kb (OVAMet258-264, VSVNP52-59, and SVNP324-332) or H2-Db (SVNP324-332, and IVNP366-374). In contrast, N-formyl-OVAMet258-264 did bind to H2-M3a. 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-M3a in presentation of N-formylated peptides such as derived from intracellular prokaryotic parasites.
Shawar
S M
SM
Department of Microbiology and Immunology, Baylor College of Medicine, Houston, TX 77030.
Vyas
J M
JM
Shen
E
E
Rodgers
J R
JR
Rich
R R
RR
D000478:Alkylation; D000595:Amino Acid Sequence; D000818:Animals; D000956:Antigens, Viral / Q000737:chemistry / Q000276:immunology; D002478:Cells, Cultured; D003602:Cytotoxicity, Immunologic; D000939:Epitopes; D005561:Formates / Q000737:chemistry; D006183:H-2 Antigens / Q000378:metabolism*; D066298:In Vitro Techniques; D051379:Mice; D008969:Molecular Sequence Data; D019590:Nucleocapsid Proteins; D009698:Nucleoproteins; D010047:Ovalbumin / Q000737:chemistry / Q000276:immunology; D010222:Parainfluenza Virus 1, Human / Q000276:immunology; D010455:Peptides / Q000276:immunology* / Q000378:metabolism; D011485:Protein Binding; D013329:Structure-Activity Relationship; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology*; D014721:Vesicular stomatitis Indiana virus / Q000276:immunology; D014758:Viral Core Proteins / Q000737:chemistry / Q000276:immunology
D000956:Antigens, Viral; D000939:Epitopes; D005561:Formates; D006183:H-2 Antigens; D019590:Nucleocapsid Proteins; D009698:Nucleoproteins; D010455:Peptides; D014758:Viral Core Proteins; C030544:formic acid; D010047:Ovalbumin