Low-affinity IgE receptor (CD23) function on mouse B cells: role in IgE-dependent antigen focusing.
B-cell surface immunoglobulin very efficiently focuses specific protein antigens for presentation to T cells. We have demonstrated a similar role in antigen focusing for the low-affinity Fc epsilon receptor (Fc epsilon RII) on mouse B lymphocytes. B cells treated with an IgE monoclonal antibody to 2,4,6-trinitrophenyl (TNP) (IgE-B cells) were 100-fold more effective than were untreated B cells in presenting low concentrations of TNP-antigen to T cells. Blocking the binding of IgE to Fc epsilon RII on IgE-B cells with a monoclonal antibody to Fc epsilon RII completely eliminated this increased effectiveness. Preformed complexes of IgE anti-TNP and TNP-antigen were more effectively presented (approximately 100-fold) than TNP-antigen in the presence of nonspecific IgE. In contrast, complexes of IgG1 anti-TNP and TNP-antigen, capable of binding to Fc gamma receptors on B cells, were presented less effectively than TNP-antigen in the presence of nonspecific IgG1. Antigens focused by means of Fc epsilon RII or by means of B-cell surface immunoglobulin receptors were presented at comparably low concentrations. For several reasons, Fc epsilon RII on B lymphocytes seems to be particularly effective in efficiently focusing IgE-antigen complexes.
Kehry
M R
MR
Department of Immunology, DNAX Research Institute of Molecular and Cellular Biology, Inc., Palo Alto, CA 94304-1104.
Yamashita
L C
LC
D000818:Animals; D000911:Antibodies, Monoclonal; D000938:Antigen-Presenting Cells / Q000276:immunology*; D000944:Antigens, Differentiation, B-Lymphocyte / Q000276:immunology*; D001402:B-Lymphocytes / Q000276:immunology*; D007073:Immunoglobulin E / Q000276:immunology*; D007700:Kinetics; D008213:Lymphocyte Activation; D051379:Mice; D008807:Mice, Inbred BALB C; D011961:Receptors, Fc / Q000276:immunology*; D017455:Receptors, IgE; D013601:T-Lymphocytes / Q000276:immunology; D014301:Trinitrobenzenes / Q000276:immunology
D000911:Antibodies, Monoclonal; D000944:Antigens, Differentiation, B-Lymphocyte; D011961:Receptors, Fc; D017455:Receptors, IgE; D014301:Trinitrobenzenes; D007073:Immunoglobulin E