Regulation of expression of a family of cross-reactive idiotypes.

It has recently been shown that anti-p-azophenylarsonate antibodies of A/J mice, which share a common idiotype, are not homogeneous but actually comprise a family of idiotypically related molecules. To obtain additional insight into the degree of relatedness of antibodies within this family, we have determined whether inoculation of any idiotype-positive hybridoma product, conjugated to thymocytes, can activate a regulatory mechanism capable of controlling the entire cross-reactive idiotypic response. In addition anti-idiotypic antibodies were prepared against individual hybridoma products, and their suppressive effects on the idiotypic component of the humoral response were determined. Inoculation of each of the idiotype-positive hybridoma products or anti-idiotypic antisera caused virtually complete suppression of the idiotypic component of the immune response. Furthermore, it was shown that the state of suppression induced by the inoculation of a hybridoma products could be adoptively transferred with T cells to mildly irradiated syngeneic recipients. The results indicate that there are sufficient structural similarities among the family of antibodies comprising the major cross-reactive idiotype to permit their recognition by the same set of elements involved in idiotypic regulation.