Relation of intra-splenic migration of marginal zone B cells to antigen localization on follicular dendritic cells.

Injection of heat-killed Escherichia coli into rats results in massive loss of IgM + ve, IgD - ve B cells from the marginal zones of their spleen within 4 hr. 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 about 16 hr, but the histological picture returns to normal within 24 hr. 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 hr post-endotoxin administration localized poorly on follicular dendritic cells. While C3 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.