Identification of an endogenous mammary tumor virus involved in the clonal deletion of Vβ2 T cells

摘要

AbstractExpression of Vβ (β ‐chain variable region) gene segments was investigated in theMus m. domesticusDDO strain, which possesses a large genomic deletion encompassing 20 of the 29 Vβ gene segments known in BALB/c. Stainings using Vβ ‐specific monoclonal antibodies revealed that up to 60 of the peripheral T cells use 3 Vβ gene segments. Variable frequencies of Vβ 2 T cells were observed among DDO individuals. Segregation analyses of F2 crosses between Vβ 2‐deletor mice and mammary tumor virus (Mtv)‐free mice led to the identification of a new endogenous Mtv, named Mtv‐DDO, mediating Vβ 2 Tcell clonal deletion. Mtv‐DDO structure is conserved with the exception of the carboxy‐terminal region as compared to other Mtv. Comparison between Mtv sharing the same Vβ specificity and isolated from laboratory or wild mice confirms that a stretch of 11 amino acids, defined as the Vβ ‐specific region, is required for the Vβ ‐specific interaction. Limited substitutions in this region account for the shift of the Mtv spec