High frequency expression of S107 V_H genes by peritoneal B cells of B10.H-2^aH-4^bP/WTS mice

Our previous analyses of peritoneal Ly-1 B cells indicate that a high percentage express V_H genes of the V_H11 and V_H12 families, and that this bias is due to clonal selection. The antibodies encoded by these genes bind the same hapten, phosphatidyl choline (PtC). Twenty-one of 73 hybridomas generated from fusions with peritoneal Ly-1 and Ly-1 sister population B cells of B10.H-2^aH-4^bp/Wts mice produce anti-PtC specific antibodies. We show here that 19 of these express V_H11 and V_H12 family genes and two express V_H36-60 family genes. To assess whether there is a bias in V_H gene use among non-PtC-specific hybridomas we analyzed the remaining 52 hybridomas for V_H family expression by using V_H family-specific probes in an RNA dot blot assay and by Ig mRNA sequencing. We find a seven-fold increase in the expression of the V_HS107 family genes, and only slight differences in the expression of V_H genes of other families relative to splenic B cells. We attribute the increase in V_HS107 gene expression to clonal selection inasmuch as five of the seven V_HS107⁺ hybridomas express the same V_H gene (V11) and V_L association is nonrandom. The bias in V_H gene use among the entire panel of 73 peritoneal hybridomas is to the extent that approximately one-third express one of three genes: the V11 gene of the S107 family, the CH34 gene of the V_H11 family, and the V_H12 family gene.