title: An appraisal of Fc receptors on human peripheral blood B and L lymphocytes.
abstract: Human circulating lymphocytes with easily detectable surface immunoglobulin have been divided into two populations, B cells and L cells. This second population lacks membrane-incorporated Ig, but has a receptor for membrane-labile cytophilic IgG. In this study purified B and L lymphocytes were examined for Fc receptors that bind aggregated IgG and IgG complexed to erythrocytes. Purified lymphocyte populations were prepared by nylon columns and by negative selection with rosetting techniques. L lymphocytes bound aggregated guinea pig and human IgG, and formed rosettes with human erythrocytes sensitized with Ripley IgG (EA). Treatment of L lymphocytes with trypsin had no effect on the receptors for IgG. B lymphocytes did not bind EA and attachment of aggregated IgG was variable; up to one-third of these cells fixed aggregated human IgG to the cell membrane. Trypsin treatment abolished binding of Agg-IgG to B cells in sharp contrast to its effect on L cells. Furthermore, double-label immunofluorescence studies showed that cells with both membrane-incorporated Ig and receptors for aggregated guinea pig IgG were rare. These studies indicate that human peripheral blood B lymphocytes lack a high affinity, trypsin-resistant Fc receptor that is present on L lymphocytes.
mesh_terms: D001402:B-Lymphocytes / Q000276:immunology*; D001666:Binding Sites, Antibody; D001769:Blood; D006801:Humans; D007141:Immunoglobulin Fc Fragments; D007074:Immunoglobulin G; D008214:Lymphocytes / Q000276:immunology*; D011947:Receptors, Antigen, B-Cell / Q000032:analysis; D013499:Surface Properties; D014357:Trypsin
chemical_list: D007141:Immunoglobulin Fc Fragments; D007074:Immunoglobulin G; D011947:Receptors, Antigen, B-Cell; D014357:Trypsin