Crossreacting human lymphoma idiotypes.

We have examined an unselected series of 72 lymphomas of diverse histologies with a panel of mouse monoclonal antibodies specific for human B-lymphoma-derived Ig idiotypes (anti-ids) to determine the nature and extent of id/anti-id crossreactivity. The anti-id antibodies were prepared from Ig isolated from seven follicular center cell lymphomas by heterohybridoma technique. Thirty-six of 75 individual anti-ids obtained in this manner were further selected based on their reactivity with highly restricted or private idiotypic determinants. Twelve of the 72 (17%) lymphoma biopsies reacted with one or more of the 36 anti-ids that detect private determinants. A pool consisting of five individual antibodies would have detected 11 of the 12 crossreacting tumors. Staining of tumor cell populations was homogeneous in the positive cases, suggesting uniform idiotype expression. If there was a segregated staining pattern, it was generally related to the presence of CD3+ T cells in the section. These follicular center cell-derived anti-ids cross-reacted with follicular center cell tumors of all histologic grades with frequencies ranging from 13% to 50%. The structural basis for the crossreactivity of our lymphoma-derived private anti-ids is as yet not known. However, the reactivity of certain anti-ids with both kappa- and lambda-expressing tumors suggests a biased use of V gene segments in these crossreactive clones that is probably related to the VH gene. These data suggest the possibility that lymphoma may develop in a highly restricted pool of normal differentiated B cells or in B-cell subsets that express a limited repertoire of unmutated VH gene segments.