title: Tolerogenicity of resting and activated B cells.
abstract: Antigen presentation by resting splenic B cells has been shown previously to induce T helper 1 cell (Th1) anergy. In contrast to expectations, it was found here that B cells treated with F(ab')2 goat anti-mouse immunoglobulin (IgM) for 24 or 48 h also presented antigen (Ag) to Th1 cells in a manner that induced dramatic Ag-specific proliferative inactivation. The tolerogenicity of the anti-Ig-treated B cells was consistent with the observation that these B cells were only slightly more efficient than resting B cells in stimulating human gamma globulin (HGG)-induced proliferation of HGG-specific Th1 cells in primary cultures. The activated B cells were, however, more efficient than resting B cells in stimulating a primary mixed leukocyte reaction, and exhibited increased expression of major histocompatibility complex class II molecules, RL388 Ag and transferrin receptor. In addition, unlike resting B cells, which expressed little detectable B7, anti-Ig-treated B cells expressed high levels of B7. The functional capacity of the B7 expressed on the activated B cells was demonstrated by the fact that the Ag-presenting capacity of these B cells was inhibited by the addition to culture of CTLA4Ig, a soluble receptor for B7. It is unlikely that the tolerogenicity of the activated B cells was due to an inability of the Th1 cells to respond to B7 signals; the Th1 clones used in the experiments, unlike the Th2 clones tested, expressed CD28, the ligand for B7. In addition, anti-CD28 monoclonal antibody inhibited the induction of Th1 cell anergy when added to cultures of Th1 cells and Ag-pulsed fixed antigen-presenting cells. Taken together, the results indicate that B cells, even when activated, do not satisfy the costimulatory requirements of the Th1 cells used here, and therefore can present Ag in a tolerogenic fashion to Th1 cells. The costimulator deficiency of activated B cells may reflect an inadequacy in the level of B7 expressed or a lack of some other molecule.
authors.affiliation: Department of Immunology, Scripps Research Institute, La Jolla, California 92037.
authors.forename: K M
authors.initials: KM
authors.lastname: Gilbert
authors.forename: W O
authors.initials: WO
authors.lastname: Weigle
mesh_terms: D000818:Animals; D000938:Antigen-Presenting Cells / Q000276:immunology*; D001402:B-Lymphocytes / Q000276:immunology*; D018122:B7-1 Antigen / Q000276:immunology; D018106:CD28 Antigens / Q000276:immunology; D002478:Cells, Cultured; D005260:Female; D006801:Humans; D007108:Immune Tolerance; D008213:Lymphocyte Activation; D008297:Male; D051379:Mice; D051381:Rats
chemical_list: D018122:B7-1 Antigen; D018106:CD28 Antigens