ENDOGENOUS IMMUNOGLOBULIN EXPRESSION IN MU-TRANSGENIC MICE

Transgenic mice (M54) containing a functional mu heavy chain were examined to determine the effects of the transgene on rearrangement and expression of endogenous immunoglobulin genes. Two major novel findings are presented. (i) In transgenic mice, the expressed endogenous V(H) repertoire in LPS-generated B cell blasts and hybridomas is skewed toward expression of J(H)-proximal V(H) families (V(H)7183 and Q52). (ii) There is an increase in the frequency of B cells expressing lambda light chain genes in transgenic mice. Furthermore, in Abelson - MuLV transformed pre-B cells, V(H) to DJ(H) is inhibited more than the D to J(H) rearrangement. The results presented indicate that the transgene skews the expressed V(H) repertoire by inhibiting the V(H) to DJ(H) rearrangement while permitting an expansion of B cells expressing limited V(H) and lambda light chain genes.