Synchronous deletion of Mtv-superantigen-reactive thymocytes in the CD3(medium/high) CD4(+)CD8(+) subset

Multiple model systems have demonstrated that negatively selected thymocyte s can be deleted during the immature CD4(+)CD8(+) CD3(low) stage after high affinity interaction of T-cell receptors (TCRs) with antigen:major histoco mpatibility complex (MHC) complexes. Superantigens (SAGs) derived from endo genous mammary tumour viruses (Mtv) induce negative selection of Mtv-SAG-re active thymocytes regardless of which peptide antigen is presented by MHC m olecules. In this study, the timing of deletion of multiple subsets of Mtv- SAG-reactive CD4(+)CD8(+) thymocytes was investigated by a 4 colour flow cy tometry in SJL x CBA/J cross-bred mice. Deletion of V beta3(+), V beta5(+), V beta 11(+), and V beta 17(+) Mtv-SAG-reactive thymocytes was found to oc cur synchronously in the most mature CD3(medium) and early CD3(high) subset s of CD4(+)CD8(+) thymocytes, in contrast with reports showing that the del etion of Mtv-SAG-reactive thymocytes can occur at different stages in parti cular model systems.