Immunologic memory to phosphocholine. VII. Lack of T15 VI gene utilization in Xid anti-PC hybridomas

CBA/N mice carrying the Xid defect fail to make antibodies expressing the T15 idiotype in response to immunization with PC-KLH. Antibodies predominating in the Xid response have binding properties characteristic of group II antibodies that emerge in the memory response in BALB/c; the prototype group II antibody utilizes a V(H) gene product distinct from the V1 gene product expressed by T15 idiotype-positive antibodies. To examine V(H) gene usage in the anti-PC response of Xid B cells, hybridomas were produced from Xid mice immune to PC-KLH. Four hybridomas possessing properties typical of the predominant group II antibody response in Xid mice and two representing minor components of the response were studied. Analysis of DNA by Southern blot hybridization revealed that none of the hybridomas utilized the T15 V1 gene segment, nor did they share use of a common VDJ gene product. These results indicate that Xid group II antibodies either make use of different V(H) gene segments or use the same V(H) in combination with various D and J(H) segments.