title: Conversion of a tolerogenic to an immunogenic signal by P388AD.2 cells, a lymphoid dendritic cell-like tumor line.
abstract: The lymphoid dendritic cell-like tumor P388AD.2 is capable of converting a tolerogenic signal into an immunogenic one. In the present study, adherent P388AD.2 cells were pulsed with the tolerogen, fluoresceinated (FL) sheep gamma-globulin (SGG), washed, and incubated with normal spleen cells. After 24 hr, the spleen cells were harvested and challenged in secondary cultures with immunogenic doses of FL-thymic independent (TI) antigens. The plaque-forming cell response on day 3 of secondary culture was increased as much as 400% compared with control spleen cultures exposed to untreated P388AD.2 cells. The increased response was specific for the FL-hapten and occurred only when P388AD.2 cells were pulsed with FL-Ig or FL-F(ab')2 fragments, but not with FL-synthetic tolerogens or other FL-antigens. Furthermore, the augmentation required histocompatible T cells in the primary cultures. Additional experiments showed that if cultures were devoid of Lyt-1+ cells but not Lyt-2+ cells, no augmentation occurred. A variety of other macrophage-like tumor cells, some with known antigen presenting properties, were tested for the ability to present tolerogen in an immunogenic fashion. Only an I-A+ J774 clone was able to present tolerogen in an immunogenic fashion. However, we failed to find a correlation between the presence of surface Ia antigen and tolerogen-presenting ability. The results suggest that certain types of cells may play a role in immune regulation by abrogating the tolerogenicity of Ig tolerogens via their presentation in an immunogenic mode.
mesh_terms: D000818:Animals; D000917:Antibody Formation; D002460:Cell Line; D000939:Epitopes; D006183:H-2 Antigens / Q000235:genetics / Q000276:immunology; D006241:Haptens / Q000276:immunology; D000949:Histocompatibility Antigens Class II / Q000235:genetics / Q000276:immunology; D007108:Immune Tolerance; D007941:Leukemia P388 / Q000276:immunology*; D007942:Leukemia, Experimental / Q000276:immunology*; D008213:Lymphocyte Activation; D008211:Lymphocyte Cooperation; D008297:Male; D051379:Mice; D008808:Mice, Inbred CBA; D051381:Rats; D011917:Rats, Inbred Lew; D013601:T-Lymphocytes / Q000276:immunology*; D005719:gamma-Globulins / Q000276:immunology
chemical_list: D000939:Epitopes; D006183:H-2 Antigens; D006241:Haptens; D000949:Histocompatibility Antigens Class II; D005719:gamma-Globulins