The TCR Vbeta 8 family consists of three members, namely Vbeta8.1, 8.2 and 8.3. KJ16-133.18 reacts with Vbeta8.1, 8.2 only, but not Vbeta8.3. Most mouse strains have about 20% Vbeta 8+ T cells in the periphery.However, C57BR, C57L, SJL, SWR (Tcra haplotype) and RIII strains (Tcrc haplotype) do not express Vbeta8 due to a gene deletion at the Vbeta 8 family loci.Other strains expressing endogenous super-antigen, such as Mls-1a have significant reduced number of Vbeta 8.1 cells in the periphery.Exogenous superantigen, such as staphylococcal enterotoxin B, stimulates lymphocytes bearing Vbeta 8 and selectively eliminate those T cells in vivo.