IgE-antigen complexes enhance Fc epsilon R and Ia expression by murine B lymphocytes.
Murine monoclonal IgE interacts with B cells of BALB/c mouse spleen with greater efficiency in the presence of its specific antigen. Complexes of anti-DNP IgE and DNP-OVA not only resist elution from B lymphocytes by acid but have a substantially longer dissociation half-time when compared with monomeric IgE (440 vs. 8 min, respectively). Further, these IgE-antigen complexes induce Fc epsilon R expression in lymphoid cells more efficiently than IgE alone. Maximum levels of B cell Fc epsilon R were observed after a 24 h incubation with 1 microgram/ml IgE in the presence of 1 microgram/ml DNP-OVA, while 30 micrograms/ml monomeric IgE was needed to elicit a similar increase of Fc epsilon R expression. Most importantly, overnight incubation of B cell-enriched BALB/c spleen cells with IgE-antigen complexes resulted in an augmented membrane expression of class II MHC antigens. B cell surface expression of both I-A and I-E antigens responded to a comparable level after incubation with IgE-antigen complexes but did not occur in response to either IgE or antigen alone. The enhanced sIa expression occurred in parallel to IgE-antigen concentrations that gave rise to Fc epsilon R hyperexpression. Moreover, double staining for Fc epsilon R and surface Ia antigen shows that B cells exhibiting the highest density of Fc epsilon R also demonstrated the most surface I-A, suggesting that B lymphocytes are autonomous in their response to IgE-antigen complexes. Changes in class I MHC or sIgM were not observed after overnight incubation with IgE and antigen. These results demonstrate the importance of IgE-antigen complexes for intercellular signaling and further suggest that the IgE system plays a broader role in immune response than it has generally been credited.
Richards
M L
ML
Division of Immunology, Medical Biology Institute, La Jolla, California 92037.
Marcelletti
J F
JF
Katz
D H
DH
D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology*; D000936:Antigen-Antibody Complex / Q000276:immunology*; D000954:Antigens, Surface / Q000032:analysis / Q000276:immunology; D001402:B-Lymphocytes / Q000166:cytology / Q000276:immunology*; D002453:Cell Cycle; D002478:Cells, Cultured; D005434:Flow Cytometry; D007073:Immunoglobulin E / Q000276:immunology*; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D011961:Receptors, Fc / Q000276:immunology*; D017455:Receptors, IgE; D013154:Spleen / Q000276:immunology
D000911:Antibodies, Monoclonal; D000936:Antigen-Antibody Complex; D000954:Antigens, Surface; D011961:Receptors, Fc; D017455:Receptors, IgE; D007073:Immunoglobulin E