Clonal deletion of thymic mature T cells induced by staphylococcal enterotoxin B in murine fetal thymus organ culture.
The present study aims at investigating the intrathymic maturational stage of T cells at which clonal deletion can be induced. Staphylococcal enterotoxin B (SEB) was added to organ cultures of murine fetal thymus lobes at various time points of culture, and V beta 8-expressing cells were assayed on day 14. V beta 8 low-expressing (V beta 8lo) cells were reduced to 40-60% of the control receiving no SEB, though the reduction was ambiguous when SEB was given on day 13. In marked contrast, V beta 8 high-expressing (V beta 8hi) cells were virtually completely deleted in all groups including the group given SEB on day 13. Most of the V beta 8hi cells that were deleted by 24 h of treatment with SEB were shown to be of the CD4+8- mature phenotype, though CD4-8+V beta 8hi cells were also deleted. It was further shown that the thymic V beta 8hi CD4+8- cells recovered from organs cultured for 14 days without SEB responded to immobilized anti-V beta 8 monoclonal antibody, indicating that V beta 8hi cells, which were highly sensitive to clonal deletion, were functionally competent mature T cells. These results strongly suggest that the thymus is capable of eliminating all T cells recognizing antigen present in the thymus regardless of the maturational stage of T cells.
Aiba
Y
Y
Department of Immunology, Faculty of Science, Kyoto University, Japan.
Mazda
O
O
Matsuzaki
Y
Y
Nakauchi
H
H
Muramatsu
S
S
Katsura
Y
Y
D000818:Animals; D000942:Antigens, Bacterial / Q000276:immunology*; D002999:Clone Cells; D003513:Cycloheximide / Q000494:pharmacology; D004768:Enterotoxins / Q000276:immunology*; D007108:Immune Tolerance; D008213:Lymphocyte Activation; D008212:Lymphocyte Depletion; D051379:Mice; D008809:Mice, Inbred C3H; D009924:Organ Culture Techniques; D016176:T-Lymphocyte Subsets / Q000276:immunology*; D013950:Thymus Gland / Q000166:cytology / Q000196:embryology / Q000276:immunology*
D000942:Antigens, Bacterial; D004768:Enterotoxins; C031818:enterotoxin B, staphylococcal; D003513:Cycloheximide