A hole in the T cell repertoire specific for a pigeon cytochrome c related peptide associated with amino acid substitutions on I-Ab molecules.
When C57BL/10(B10) mice were immunized with a pigeon cytochrome c related peptide, 50V (AEGFSYTVANKNKGIT), two helper T cell populations with different specificity were activated. A major T cell population reacted with a 50V analog, 50V54A (AEGFSYTVANKAKGIT), more potently than with the immunogen, 50V, in a heteroclitic fashion, whereas the other minor T cell population responded only to 50V. By contrast, when bm12 mice were immunized with 50V, the minor T cell population responding only to 50V could hardly be demonstrated. The apparent deletion of the minor T cell population in bm12 mice seems to be attributable to negative selection under the influence of I-Abm12 molecules, since the minor T cell population was undetectable in both I-Ab and I-Abm12 restricted T cells from (B10 x bm12)F1 mice. Thus, three mutant points on the I-A molecule in bm12 mice appear to be involved in the seemingly negative selection of the certain T cell repertoire. The present finding demonstrates that a T cell repertoire generated under the influence of a MHC product (Ab) on one parental strain is eliminated by a different MHC product (Abm12) on the other parental strain of F1 cross. The mechanism underlying the apparent negative selection is discussed.
Itoh
Y
Y
Section of Pathology, Institute of Immunological Science, Hokkaido University, Sapporo, Japan.
Ogasawara
K
K
Gotohda
T
T
Takami
K
K
Naruse
H
H
Onoe
K
K
D000595:Amino Acid Sequence; D000818:Animals; D010856:Columbidae; D003574:Cytochrome c Group / Q000235:genetics / Q000276:immunology*; D000949:Histocompatibility Antigens Class II / Q000235:genetics / Q000276:immunology*; D007108:Immune Tolerance; D007114:Immunization; D008213:Lymphocyte Activation; D051379:Mice; D008810:Mice, Inbred C57BL; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D013601:T-Lymphocytes / Q000276:immunology*
D003574:Cytochrome c Group; D000949:Histocompatibility Antigens Class II