Chronic deletion, escape from deletion and activation of mouse mammary tumor virus superantigen-reactive T cells in C57BL/10 mice.
Though C57BL/10 mice express the mouse mammary tumor virus superantigens (sag) encoded by Mtv-8 and Mtv-9, it has been thought that these sag do not bind to the MHC class II molecule H2-Ab and consequently do not affect the T cell repertoire. However, we show that cells bearing TCR Vbeta chains specific for Mtv-8 and -9 sag are chronically deleted in C57BL/10 mice. Thymocytes and peripheral T cells escaping deletion by Mtv sag display a small reduction in the level of cell surface CD4. T cells escaping thymic deletion respond variably to endogenous Mtv sag with some, but not all, reactive populations appearing overrepresented in the activated/memory subset. The data suggest that in normal mice fine modulation of coreceptor expression levels may be a common way by which thymocytes escape elimination, that systems utilizing potentially Mtv sag-reactive TCR on a C57BL background may be inappropriate for the measurement of the affinity of TCR/MHC/peptide interactions required in thymic selection, and that detection of the activity of human sag may be aided by analysis of CD4 levels and activation markers on T cells in conjunction with studies of the frequency of cells bearing specific TCRVbeta chains.
Dyson
P J
PJ
Transplantation Biology Group, MRC Clinical Sciences Centre, Imperial College School of Medicine, Hammersmith Hospital, London, GB.
Elliott
J I
JI
D000818:Animals; D000956:Antigens, Viral / Q000276:immunology*; D015704:CD4 Antigens / Q000276:immunology; D006183:H-2 Antigens / Q000276:immunology; D006801:Humans; D008213:Lymphocyte Activation / Q000276:immunology; D008212:Lymphocyte Depletion; D008324:Mammary Tumor Virus, Mouse / Q000276:immunology*; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D016688:Mice, Inbred NOD; D018089:Superantigens / Q000276:immunology*; D013601:T-Lymphocytes / Q000276:immunology*
D000956:Antigens, Viral; D015704:CD4 Antigens; D006183:H-2 Antigens; C108513:H-2A antigen; D018089:Superantigens