title: In vivo treatment with monoclonal anti-I-A antibodies: disappearance of splenic antigen-presenting cell function concomitant with modulation of splenic cell surface I-A and I-E antigens.
abstract: A single injection of anti-I-Ak antibody (AB) into H-2k mice resulted in abrogation of splenic antigen-presenting cell (APC) function for protein antigen-primed T cells or alloantigen-specific T cells. Spleen cells from anti-I-A-treated mice are not inhibitory in cell mixing experiments when using cloned antigen-specific T cells as indicator cells, thus excluding a role for suppressor cells in the observed defect. Also, nonspecific toxic effects and carry-over of blocking Ab were excluded as causes for the defect. Experiments with anti-I-Ak Ab in (H-2b X H-2k)F1 mice showed abrogation of APC function for T cells specific for both parental I-A haplotypes. In homozygous H-2k mice, anti-I-Ak treatment not only abrogated APC function for I-Ak-restricted cloned T cells but also for I-AekE alpha k-restricted cloned T cells. FACS analysis of spleen cells from anti-I-Ak-treated (H-2b X H-2k)F1 mice revealed the disappearance of all Ia antigens (both I-A and I-E determined), whereas the number of IgM-bearing cells was unaffected. The reappearance of APC function with time after injection was correlated with the reappearance of I-A and I-E antigen expression. In vitro incubation of spleen cells from anti-I-A-treated mice led to the reappearance of Ia antigen expression and APC function within 8 hr. Thus, it appears that B cells (as determined by FACS analysis) and APC (as determined by functional analysis) behave similarly in response to in vivo anti-I-A Ab treatment. We interpret these findings as suggesting that in vivo anti-I-A treatment temporarily reduces the expression of Ia molecules through co-modulation on all Ia-bearing spleen cells, thereby rendering them incompetent as APC. Such modulation of Ia molecules does not occur when spleen cells are incubated in vitro with anti-I-A antibodies. These results imply that a primary defect purely at the level of APC in anti-I-A-treated mice may be responsible for the observed T cell nonresponsiveness when such mice are subsequently primed with antigen.
authors.forename: A M
authors.initials: AM
authors.lastname: Kruisbeek
authors.forename: J A
authors.initials: JA
authors.lastname: Titus
authors.forename: D A
authors.initials: DA
authors.lastname: Stephany
authors.forename: B L
authors.initials: BL
authors.lastname: Gause
authors.forename: D L
authors.initials: DL
authors.lastname: Longo
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000008:administration & dosage*; D000918:Antibody Specificity; D000938:Antigen-Presenting Cells / Q000145:classification / Q000276:immunology*; D001831:Body Temperature; D004306:Dose-Response Relationship, Immunologic; D000939:Epitopes / Q000276:immunology; D006649:Histocompatibility Antigens / Q000235:genetics / Q000276:immunology*; D000949:Histocompatibility Antigens Class II / Q000032:analysis / Q000235:genetics / Q000276:immunology*; D007108:Immune Tolerance; D008213:Lymphocyte Activation; D051379:Mice; D008807:Mice, Inbred BALB C; D008809:Mice, Inbred C3H; D008810:Mice, Inbred C57BL; D013154:Spleen / Q000166:cytology; D013997:Time Factors; D014373:Tuberculin / Q000276:immunology
chemical_list: D000911:Antibodies, Monoclonal; D000939:Epitopes; D006649:Histocompatibility Antigens; D000949:Histocompatibility Antigens Class II; C024138:I-E-antigen; D014373:Tuberculin