Further Studies on Amplification of Cell‐Associated Immunological Memory by Secondary Antigenic Stimulus

Abstract

AbstractUsing the hapten‐carrier system in which the dinitrophenyl group (DNP) served as a B cell reactive hapten and bovine serum albumin (BSA) or human gammaglobulin (HGG) as a T cell reactive carrier, changes in the hapten‐specific memory (B cell‐associated memory) and the carrier‐specific memory (T cell‐associated memory) after a secondary antigenic stimulus were analyzed in mice. Since an immunological adjuvant was indispensable in the induction of the primary increase in memory, antigen used for the primary antigenic stimulus was injected together with the capsular polysaccharide of Klebsiella pneumoniae (CPS‐K) which has already been shown to exhibit a potent adjuvant effect. With the cell‐transfer technique, it was found that the cell‐associated hapten‐specific memory for anti‐DNP antibody response to DNP‐BSA was truly amplified by the secondary injection of DNP‐HGG into mice primed with DNP‐HGG, and that the cell‐associated carrier‐specific memory as judged by the helper effect on anti‐DNP response to DNP‐BSA was also truly amplified by the secondary injection of BSA into mice primed with BSA. However, when memory was assessed in actively immunized mice, the secondary injection of BSA into mice primed with DNP‐BSA and HGG decreased anti‐DNP responsiveness to the tertiary injection of DNP‐BSA, whereas the secondary injection of DNP‐HGG secondarily increased anti‐DNP responsiveness. In mice primed with DNP‐BSA the titers of serum antibodies to BSA increased after the secondary injection of DNP‐BSA or BSA. From these results it has been concluded that, like B cell‐associated memory, T cell‐associated memory is also amplified by a secondary antigenic stimulus, although its expression is inhibited in actively immunized mice through negative control by their antibodies.