THE HUMAN-ANTIBODY REPERTOIRE - HEAVY AND LIGHT-CHAIN VARIABLE REGIONGENE USAGE IN 6 ALLOANTIBODIES SPECIFIC FOR HUMAN HLA CLASS-I AND CLASS-II ALLOANTIGENS

Peripheral blood B lymphocytes have been isolated from healthy individ uals who were immunized with lymphocytes from HLA-incompatible donors and transformed with Epstein-Barr virus to produce human monoclonal ce ll lines specific for human HL.4 molecules. The cell lines have been p reviously characterized and are known to bind to various class I and c lass II alloantigens. In this report we describe the molecular charact erization of the heavy and light chain variable region gene segments t hat are utilized by these monoclonal antibodies. Using the polymerase chain reaction and primer pairs specific for the respective constant r egion and V-H or V-L family, rearranged variable region gene segments were amplified from cDNA from individual cell lines. Products were the n subcloned, sequenced and analysed for gene usage and apparent somati c mutation. The results show that the V(H)3 gene family predominates i n a group of six heavy chains (four out of six) with one V(H)1 and one V(H)4 gene segment. The light chain variable region gene family usage is more diverse with 2 V(kappa)3, 1 V(kappa)1, 2 V(lambda)2 and 1 V(l ambda)3. The extent of apparent somatic mutation is minimal, relative to our previous observations in a group of high affinity human monoclo nal antibodies specific for pathogenic organisms.