Molecular comparison of cultured hybridoma cells that switch isotypes at high and low rates

We have previously reported the isolation of variants from the 36.65 and PCI.4.1 hybridoma cell lines that spontaneously switch from γ1 to γ2a and γ2b at high and low rates. In order to further characterize the phenotype of these variants, we have now investigated the production of germline transcripts and methylation which are two of the molecular correlates of isotype switching. While some of the correlations that exist in normal cells were present in some of the clonal variants, others were not. However, the higher switching variants of both cell lines had higher recombinational activity as measured with a shuttle vector. The distinct phenotypic characteristics of each cell line provide an opportunity to dissect the roles of individual molecular events in the process of isotype switching.