Characterization of the antibody response to type 3 pneumococcal polysaccharide at the cellular level. II. Studies on the relative rate of antibody synthesis and release by antibody-producing cells.

A procedure based on the rate of appearance of plaque-forming cells (PFC) in agarose was used to measure the relative rates of antibody synthesis and release by cells making antibody specific for Type III pneumococcal polysaccharide (SSS-III). The rate of antibody synthesis and release by SSS-III-specific PFC was directly related to the immunizing dose employed; maximal values were obtained with mice given an optimally immunogenic dose (0.5 μg) of SSS-III. However, dose-dependent reductions, not only in the magnitude of the antibody response, but also in the rate of antibody synthesis and release by specific PFC, were noted in mice receiving doses greater than 0.5 μg. The latter suggests that a decrease in the rate of antibody synthesis and release by antibody-forming cells may be an initial step in the induction of immunological paralysis by high doses of SSS-III. Increases in the magnitude of the serum antibody and the PFC response were associated with corresponding increases in the rate of antibody synthesis and release by SSS-III-specific PFC following immunization; this suggests that cell differentiation—rather than proliferation—plays a major rôle in the development of the antibody response to SSS-III. In contrast, the results obtained in similar studies with sheep erythrocytes indicate that cell proliferation influences to a greater degree the magnitude of the antibody response elicited to this antigen.