RELATION OF INTRA-SPLENIC MIGRATION OF MARGINAL ZONE B-CELLS TO ANTIGEN LOCALIZATION ON FOLLICULAR DENDRITIC CELLS

Abstract

Injection of heat-killed Escherichia coli into rats results in massive loss of IgM + ve [statistical correlation], IgD - ve B cells from the marginal zones of their spleen within 4 h. This is matched by a concomitant increase of cells with this phenotype in the splenic follicles. The marginal zone remains depleted and the follicles distended for .apprx. 16 h, but the histological picture returns to normal within 24 h. Surface marker analysis of blood and spleen B lymphocyte populations throughout the course of the migration suggest that there is intrasplenic migration of IgM + ve cells from marginal zone to follicles rather than via the circulation. Factors inhibiting localization of immune complex on follicular dendritic cells were assessed for their influence on marginal-zone B cell migration. Immune complex, injected 5 h post-endotoxin administration localized poorly on follicular dendritic cells. While C3 [complement component 3] depletion, by cobra venom, has no effect on marginal-zone B cell migration induced by endotoxin, it completely inhibits transport of heat-aggregated human gammaglobulin to follicular dendritic cells.