Two BALB/c anti-arsonate idiotype families: two heavy chain variable regions (Vh) shared with anti-DNP antibodies are used by one family while a Vh similar to anti-GAT antibodies is used by the other.

Amino terminal amino acid sequences were obtained for both the heavy (H) and light (L) chains of seven BALB/c anti-arsonate (Ar) monoclonal antibodies representing the 5AF6 and 3C6 idiotype (id) families described in this strain. 5AF6 family H chains showed strong homology to the germ-line gene sequence for the A strain 36-60 family. However, four to five identical H chain sequence differences for two of these antibodies (5AF6 and 95B5), as well as two previously reported related sequences (92D5, 94B10), suggested they were encoded by a different Vh. The 36-60 family Vh genes have been shown to be identical to the Vh gene of the anti-DNP binding myeloma M460 [Dzierzak et al., J. Immun. 136, 1864-1870 (1986)]. H chains amino acid sequences derived from an id-460+ anti-DNP hybridoma and a germ-line gene differing from the 30-60-like Vh sequence [Dzierzak et al., J. Immun. 136, 1864-1870 (1986)] were found to be virtually identical to the 95B5 and 5AF6 Vh sequences. This suggests that the same two related H chains making up two subsets of the 5AF6 anti-Ar id family are also both used in two subsets of the id-460 anti-DNP response. 5AF6 family L chains were highly homologous to the other Vk2 L chains of the 36-60 family. 3C6 family H chains can be placed in the Vh l group, are unrelated to the described anti-Ar H chain families, and have been placed in a new anti-Ar Vh family, Ars-E. The 3C6 H is similar, however, to a Vh used by a BALB/c anti-GAT idiotype family of antibodies. 3C6 L chains were of the murine kappa chain group, Vk8 and most resembled an L chain from an A strain monoclonal anti-Ar having no defined idiotype.