Memory B Cells Generated in T Cell-Dependent Antibody Responses Colonise the Splenic Marginal Zone

Abstract

The marginal zones are a major B cell compartment in both rat and human spleen. These B cells possess a distinct phenotype in that they express surface membrane IgM (slgM) with little surface membrane IgD (slgD). Although they do not recirculate as such, they are derived from recirculating precursors (1). They appear in normal numbers in congenitally athymic animals and much indirect evidence suggests they can be activated by thymus-independent type 2 (TI-2) antigens (2). However, experiments presented here indicate that some memory B cells generated during established T cell-dependent antibody responses colonise the marginal zones and take up the characteristic phenotype of marginal zone B cells. These cells have been revealed using a method developed by Claasen & Van Rooijen (3) in which haptenated enzymes are used to study the appearance of specific cells producing anti-hapten antibodies. These workers used this technique to identify antibody-secreting cells. However, during the course of the experiments reported it became clear that hapten-specific surface immunoglobulin can also be identified by this technique.