Figure 4.

Altered isotype frequencies and reduction of somatic hypermutation in hybridomas derived from 564Igi Aicda^G23S mutant mice Hybridomas were generated from the spleen and bone marrow (BM) of the indicated mice. Hybridoma culture supernatants were tested for IgG anti-RNA antibody secretion by ELISA. (A) The IgH and IgL genes of anti-RNA IgG-producing hybridomas from 564Igi and from 564Igi Aicda^G23S mice were cloned and sequenced. Sequences were compared to the original 564 immunoglobulin knock-in sequences to identify mutations. The mutation frequency is shown. (B) Igγ and Igκ genes were cloned and sequenced from anti-RNA IgG2a-secreting hybridomas generated from 564Igi spleen and BM cells. Shown is the number of mutated and unmutated sequences. The number of sequences with mutations in Igγ only, Igκ only, or Igγ and Igκ is also indicated. (C) The percent of hybridomas from (B) with the indicated number of mutations in Igγ and Igκ genes is shown. The total number of sequences analyzed for each gene is shown in the center.