Induction of Resistance to Antibody-mediated Cytotoxicity

One of the main problems in the genetic analysis of a complex antigenic system is cross-reactivity of the antibodies defining individual antigens . Because of cross-reactivity it is often difficult, if not impossible, to determine the relationship between genetic structure on the one hand and molecular interrelationships among the antigens on the other hand . Although, theoretically, such a relationship can be elucidated by biochemical methods, the biochemical approach is complicted by the uncertainty whether the isolated products represent pieces of the membrane, molecules, or molecular fragments . Moreover, the biochemical methods are still too complicated to be used routinely in an ordinary serological analysis . Recently, two methods have become available that by-pass the difficulties indigenous to the biochemical analysis, and yet provide important information about the molecular interrelationship of individual antigens . Both methods are based on the assumption that independent molecules float freely in the cell membrane (1) and can be aggregated when combined with antibodies (2) . Of the two methods, namely, redistribution of antigens after exposure to fluorescent antibodies ("capping", cf. ref. 2) and acquisition of specific resistance to complement-dependent lysis after antigen redistribution ("lyso-strip", cf. ref. 3, 4), only the former has been utilized in the studies of the mouse H-2 complex (5) . In this report we describe an application of the lysostrip method to the H-2 system and provide evidence for independent movement in the lymphocyte membrane of H-2, Ia, and Ig antigens .