A Receptor for Antibody on B Lymphocytes

Abstract

Evidence is presented for the existence on all B lymphocytes, but not on T lymphocytes, of a membrane-associated receptor for antibody. The receptor was detected by a radioautographic technique in which lymphoid cells were incubated with antibody followed by the corresponding radioiodinated antigen. The ease with which antibody eluted during washing indicated that the bond between antibody and cell was weak. The formation of an antibody-antigen complex on the cell surface, however, stabilized the bond and permitted accurate quantitation of cells with adherent antibody. The ability of several combinations of antibody and antigen to adhere to the cells demonstrated the nonspecificity of the phenomenon and emphasized the need for care in interpretation of antigen-binding studies particularly when immune cells are being used. The identity of antibody-binding lymphocytes was established by two different approaches. In the first, mouse lymphocyte populations greatly enriched for either T cells or B cells were examined. Their T cell content was assessed by means of well-established markers such as the θ C3H isoantigen. When this was compared with the number of antibody-binding cells, an inverse relationship was obtained in each instance; thus almost all thoracic duct cells from athymic mice labeled with an immune complex although none were θ positive. The striking reduction in antibody-binding cells observed in bursectomized chickens provided a second and independent line of evidence suggesting that B cells, not T cells, bind antibody. The ability of B cells from primed animals to bind antibody in vivo made it important to test whether this phenomenon was related to the carriage of immunological memory. No correlation was, however, found between membrane-bound antibody and memory. It was proposed that the existence of a receptor of this kind may provide a rational explanation for antibody-dependent killing of target cells and may prove of importance in antigen concentration particularly during the secondary response.

RECEPTORS FOR AGGREGATED IgG ON MOUSE LYMPHOCYTES

“…The reports of Basten et al (12,13) which indicated that binding of Ig was a property limited to B lymphocytes (although 2-4 % of C57/B16 thymocytes were also positive) does not permit an analysis of aggregate size since undefined ratios of antigen and antibody were used to form the aggregates assayed for in their systems. With respect to sensitivity of assay, species and tissues studied, their system was similar to that we employed.…”

Enhanced Fc receptor expression by a sub-population of murine intra-tumour macrophages following intravenous Corynebacterium parvum therapy

“…Response to C. parvum treatment in this model is T-lymphocyte dependent and tumour infiltrating T-lymphocytes may be activated simultaneously with cells of the mononuclear phagocyte series. Activated Tlymphocytes (Yoshida & Anderson, 1972) and Blymphocytes (Basten et al, 1972) express FcR which would form rosettes under the conditions used, i.e. with ORBC sensitised with high concentrations of antibody if they did contaminate the mg monolayers.…”

Immunodeviation by Passive Antibody, an Expression of Selective Immunodepression

“…Guinea pig IgG2 antibodies are cytophilic for macrophages and the strength of the binding is considerably increased when the antibody has reacted with the antigen (31). Similarly, mouse B cells have a receptor exhibiting a marked predilection for lgG1 antibody, the bond being stabilized when the antibody has reacted with the antigen (32,33). Furthermore, only IgG1 antibodies have been shown to be highly thymus dependent in the mouse (34,35).…”