SALAHUDDIN KHAN , AND KENNETH MILLAR 1185 RESULTS Effect

Since the initial description by Michaelis over a half century ago, of the effects of competition of antigens on the immune response (1), interest in this area has waxed and waned concomitant with the current views and interests of investigators in medicine and biology. Initially, workers were motivated in their studies by a practical purpose, since antigenic competition played a vital role in determining the immune responses to vaccines containing a multiplicity of antigens (2--4). In modern times, antigenic competition has been employed for diverse experimental purposes. The model has been employed as a useful tool for the study of the theory of donal selection (5), the investigation of the immune responses to two liaptens placed on the same or differing carrier molecules (6), the inhibition of the immune response to haptenic determinants bound to a single carrier or multiple carriers by passively administered antibody (7), and the maintenance of immunological tolerance and the induction of experimental autoimmunity (8). Previous work by this investigator as well as by a number of other investigators, provided evidence for the sequential production of 19S and 7S immunoglobulins by cells arising from differing progenitors (9-12). These findings implied that the induction phase of these two events in the immune response might possess important biological differences which could be delineated by a model of antigenic competition. In particular, questions were raised pertaining to the characteristics of the immune response to two antigens administered in appropriate sequence, such that the induction of the 19S or 7S response to the initial antigen coincided with the period of induction of 19S response to the second antigen.