Anti-fluorescein antibody 3-13 V_H gene rearrangement in idiotypically cross-reactive hybridomas

The deduced amino acid sequence of anti-fluorescein (F1) antibody 3-13 V_H region (residues 1-95) was 78% homologous to the α-1→ 3-dextran binding myeloma protein J558 v_h region and was in the Wu-Kabat Subgroup II or Dildrop Group I classifications. The 3-13 V_H region was rearranged to a D segment with only 8 of 30 bp in common with DFL16.1 germ line D gene and less homologous to all other previousy identified D sequences. This sequence was joined to the third codon of J_H4. The sequence encoding V_H residues 5-91 was subcloned into pSP65 and used as a probe in Southern analyses to monitor 3-13 V_H gene rearrangements in 12 other anti-F1 hybridomas differentially expressing (or not at all) the 3-13 idiotype. Three clones which inhibited the 3-13 idiotype-anti-idiotype interaction as effectively as 3-13 (3-12, 3-17 and 3-35), all had rearranged a gene which hybridized to the cloned 3-13 fragment, however, each was contained on a different size restriction fragment. Analyses of five other idiotypically related (but not identical) hybridomas indicated that four had rearranged a cross hybridizing V_Hgene while no such rearrangements were detected among four idiotyplcally negative cell lines. A restriction site assay indicated five clones examined had all rearranged a V_κ gene to the J_κ 1 or J_κ2 gene segment. The sequence of the antibody 3-13 V_H gene and its use in hybridization studies represent the first molecular analysis of a recurrently expressed repertoire specific idiotype within an unrestricted immune response.