Restricted Ig variable region gene expression among Ly-1⁺ B cell lymphomas

The majority of the characterized Ly-1⁺ B cell lymphomas of B10.H-2^aH-4^bp/Wts origin (the Ch series) bear surface Ig related by Ag specificity or idiotype or both. To determine the genetic basis for these structural similarities, we have sequenced the V(H) and V(L) region genes expressed by 10 CH lymphomas, and have compared their V(H) and V(κ) gene rearrangements by Southern blot analysis to one another and to those of four other CH lymphomas. Sequence analysis identified only five different V(H), and seven different V(L) genes, and indicated that these V genes are essentially unmutated. CH lymphomas which express the identical V(H) gene share at least one idiotope. Thus, the basis for shared idiotype and specificity is due in most cases to the use of the same V gene. This restriction in V gene expression is not due to the preferential use of V genes of any particular V(H) family or V(L) group, as the expressed V genes belong to four different V(H) families and four V(κ) groups, and include V(λ)1 and V(λ)2. We hypothesize that Ag selection accounts for the restriction in V gene usage among CH lymphomas.