Expression of a mouse Ig V gene in antibodies of three immunoglobulin classes.

In an earlier study we found that some mouse strains, including the C57BL/6, produced irregular IgG anti-(4-hydroxy-3-nitrophenyl)acetyl (NP) antibodies to protein conjugates of this hapten. This antibody had heteroclitic fine specificity and a characteristic isoelectric focusing pattern. Breeding studies suggested that these qualities of the C57BL/6 anti-NP were controlled by a V gene of the heavy chain. We have now found that this V gene is expressed in anti-NP antibodies and plaque-forming cells of all major immunoglobulin classes: IgG, IgA and IgM.