Evidence that Static but Not Recirculating B Cells are Responsible for Antibody Production Against Dinitrophenol on Neutral Polysaccharide, A TI-2 Antigen

Abstract

The peripheral B cell pool of the rat can be divided into a subpopulation that recirculates between follicles in secondary lymphoid organs and one that is static (1). A large component of the non-recirculating population is found in the marginal zones (MZ) of the spleen. MZ B cells differ from recirculating follicular (RF) B cells in lacking surface membrane (Sm) IgD. Both express Sm IgM (2). Recently, several lines of indirect evdence have emerged that infer the involvement of MZ B cells in responses to thymus-independent type-2 (TI-2) antigens: i) Rats suppressed from birth with anti-IgD antibodies develop intact MZ, but not RF B cell populations (3). ii) This treatment results in an elevation of of serum IgG2c with loss of IgG2a (3). IgG2c is the predominant isotype elicited in response to TI-2 antigens, while IgG2a is dominant in T cell-dependent responses (4). iii) Approximately 20% of MZ B cells express Sm IgG2c (3). iv) Dendritic cells within the marginal zone selectively localise neutral polysacccharides which are TI-2 antigens (5,6). v) Adult splenectomy causes a profound depression of the response to the the TI-2 antigen dinitrophenylated hydroxyethyl starch (DNP-HES), but not to DNP-haemocyanin, a thymus-dependent antigen (7).