Oligosaccharide-dependent and independent Qa-1 determinants.
A contribution of N-linked oligosaccharides to determinants recognized by alloreactive cytotoxic T lymphocytes has not been demonstrated. Employing cloned CTL and tunicamycin, an inhibitor of protein glycosylation, we found that carbohydrate addition was required for the formation of two of six Qa-1 determinants. The other determinants were detectable on nonglycosylated Qa-1 molecules, similar to observations in most reports that allodeterminants on class I molecules are not dependent on glycosylation for serologic detection. Examination of TM-treated, Con A-activated lymphoblasts revealed a direct correlation between the determinants defined by the reactivity of CTL clones with target cells from four Qa-1 genotypes and their dependence on carbohydrate side chains for expression. Most anti-Qa-1b CTL clones recognized either a glycosylation-dependent determinant found only on Qa-1b cells or glycosylation-independent determinants on both Qa-1b and Qa-1c cells. Similarly, clones that killed only Qa-1a cells recognized a glycosylation-independent determinant. However, clones reactive with both Qa-1a and Qa-1d cells recognized a glycosylation-dependent determinant on Qa-1a molecules and a glycosylation-independent determinant on Qa-1d molecules. This result indicates that such clones recognize cross-reactive conformational determinants, not carbohydrate itself. Thus, N-linked oligosaccharides serve to stabilize the conformation of some Qa-1 determinants, but others remain intact on nonglycosylated molecules. The absence of similar data for H-2K/D/L molecules suggest that a reexamination of other class I antigens with cloned CTL is in order to determine whether Qa-1 molecules are unique.
Jenkins
R N
RN
Aldrich
C J
CJ
Lopez
L A
LA
Rich
R R
RR
D000818:Animals; D000954:Antigens, Surface / Q000032:analysis / Q000235:genetics / Q000276:immunology; D002460:Cell Line; D003429:Cross Reactions; D003602:Cytotoxicity, Immunologic / Q000187:drug effects; D000939:Epitopes / Q000032:analysis / Q000235:genetics / Q000276:immunology; D015395:Histocompatibility Antigens Class I; D051379:Mice; D008805:Mice, Inbred A; D008810:Mice, Inbred C57BL; D009844:Oligosaccharides / Q000378:metabolism / Q000502:physiology; D010455:Peptides / Q000032:analysis; D011110:Polymorphism, Genetic; D011487:Protein Conformation; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology / Q000378:metabolism; D014415:Tunicamycin / Q000494:pharmacology
D000954:Antigens, Surface; D000939:Epitopes; D015395:Histocompatibility Antigens Class I; D009844:Oligosaccharides; D010455:Peptides; C032907:Q surface antigens; D014415:Tunicamycin