Unglycosylated Mtaa expresses an Mtab-like determinant.
Antigenic polymorphism of the class I-like maternally transmitted antigen (Mta) is controlled by a maternally transmitted factor (Mtf) thought to reside in mitochondria. However, the mechanisms by which Mtf generates antigenic polymorphism are not known. To address this issue, we investigated a possible role of posttranslational oligosaccharide addition in the formation of Mta determinants. We examined the expression of Mta on cytotoxic T lymphocyte (CTL) target cells cultured in tunicamycin (TM), a known inhibitor of asparagine(N)-linked glycosylation. Of 18 Mtab-specific CTL lines, 8 lysed TM-treated Mtaa targets. Furthermore, a subclone of one of these eight lines, 17D5.G2, lysed TM-treated targets from all Mtaa strains tested, regardless of H-2K/D haplotype. On the other hand, this CTL clone did not lyse TM-treated target cells from the Mta null, but H-2 expressing strain B10.CAS2. Therefore expression of this Mtab-like determinant is concordant with the expression of Mtaa and seems unlikely to represent a cross-reactive H-2K/D epitope. Our data suggest that an Mtab-like determinant is expressed on unglycosylated Mtaa molecules. Thus, N-linked oligosaccharides probably prevent the expression of an Mtab-like determinant on the Mtaa molecule. We discuss how Mtf may contribute to Mta polymorphism through glycosylation.
D000818:Animals; D000954:Antigens, Surface / Q000235:genetics / Q000276:immunology*; D002460:Cell Line; D003429:Cross Reactions; D000939:Epitopes / Q000276:immunology; D006031:Glycosylation; D016169:Lymphocyte Function-Associated Antigen-1; D051379:Mice; D008815:Mice, Inbred Strains; D011110:Polymorphism, Genetic; D013602:T-Lymphocytes, Cytotoxic / Q000187:drug effects / Q000276:immunology; D014415:Tunicamycin / Q000494:pharmacology
D000954:Antigens, Surface; D000939:Epitopes; D016169:Lymphocyte Function-Associated Antigen-1; D014415:Tunicamycin