Transition in the Character of Immunological Memory in Mice after Immunization

Abstract

The immunological memory in antibody response of mice to bovine serum albumin (BSA) was investigated at the level of antibody-producing cells or their precursor B [bone marrow-derived] cells and helper T [thymus-derived] cells. Spleen cells obtained from mice previously primed with alum-precipitated BSA at various times were transferred to irradiated syngeneic mice. Spleen cells from mice immunized 8 days or 64 days before presented a high degree of adoptive secondary response, whereas the adoptive response of cells from mice immunized 2 days previously was inferior even to that of unprimed spleen cells. Primed spleen cells treated with anti-mouse thymocyte rabbit serum plus complement were supplemented with normal thymus cells and the restoration of the responsiveness was examined. The memory was apparently carried mainly by T cells in the earlier phases of the immunological memory (2 days or 8 days after the primary immunization). The immunological memory in the B-cell population grew gradually toward the later phase (later than 40 days).