Molecular Analysis of Immunoglobulin Heavy Chain Genes Coding for Idiotypic and Anti-Idiotypic Antibodies Involved in B-B Cellular Interaction

抄録

We recently reported that a unique B cell clone (B19-1^d), specific for a cross-reactive idiotype (CRI) on MOPC104E myeloma protein (M104E), enhances Igh-restricted CRI⁺ antibody production. In this paper, we report the nucleotide sequences of immunoglobulin heavy chain variable regions (V_H) of both M104E and B19-1^d-derived hybridoma (HB19) antibodies. The sequence data revealed that both belong to the J558 germ line V_H gene subfamily. Strikingly, not only the V_H region, but also the leader sequences of M104E and HB19 are very similar to each other at 88% (V_H) and 91% (leader) homology, but they use different D and J segments. The V_H region sequence similarity is highest among the germ line V_H gene sequences of the BALB/c J558 subfamily so far screened. Southern hybridization data, using 5'-noncoding regions of either M104E or HB19 genomic V_H gene clones as probes, revealed that both V_H genes are conserved in the M104E CRI producer strains of mice. Moreover, these probes show the restriction length polymorphism pattern of mouse V_H genes in various strains. That the HB19 V_H gene locates to the 5' upper arm of the M104E V_H gene on the chromosome was suggested by Southern blot hybridization. Immunoglobulin V_H gene restriction of idiotypic and antiidiotypic B-B cellular interaction is discussed from a molecular point of view.