title: Dual effects of OK-432 on mitogenic response of splenocytes to concanavalin A.
abstract: OK-432, a streptococcal preparation, was studied for its effect on the concanavalin A (Con A)-induced mitogenesis of the host spleen cells. When mice were given a single intraperitoneal injection of OK-432, there was a substantial increase in the mitogenic response of splenocytes, whereas multiple injections conversely resulted in a marked reduction of the mitogenic response, when the spleen cells were cultured at high cell densities of over than 5 X 10(5) cells/well. The reduced Con A-responsiveness in the latter was not restored by mixing spleen cells from mice given multiple OK-432 injections with those from normal mice. Moreover, splenic macrophages from OK-432-injected mice exhibited marked inhibitory activity against Con A-mitogenesis of normal splenocytes, while normal splenic macrophages failed to show such an effect. Splenic T cells from OK-432-injected mice also showed an inhibitory activity against Con A-mitogenesis of normal splenocytes and similar activity was also noted in normal splenic T cells. Therefore, the OK-432-spleen cells contain two types of suppressor cells; one is a newly elicited suppressor macrophage and the other is a suppressor T cell supposedly resident also in normal spleen cells. In the OK-432-injected spleen cells, accessory cell function for T cell Con A-mitogenesis was markedly reduced. On the other hand, it was noted that the interleukin 2-producing ability of the OK-432-splenocytes was augmented more than that of normal splenocytes, indicating that multiple OK-432 injections also cause an increase in the helper T cell activity of the host spleen cells.
authors.forename: H
authors.initials: H
authors.lastname: Tomioka
authors.forename: H
authors.initials: H
authors.lastname: Saito
authors.forename: K
authors.initials: K
authors.lastname: Nagashima
mesh_terms: D000818:Animals; D001688:Biological Products / Q000494:pharmacology*; D003208:Concanavalin A / Q000494:pharmacology*; D007376:Interleukin-2 / Q000096:biosynthesis; D008213:Lymphocyte Activation; D008264:Macrophages / Q000276:immunology; D008297:Male; D051379:Mice; D008808:Mice, Inbred CBA; D010844:Picibanil / Q000494:pharmacology*; D013154:Spleen / Q000166:cytology; D050378:T-Lymphocytes, Regulatory / Q000276:immunology*; D013936:Thymidine / Q000378:metabolism; D013997:Time Factors
chemical_list: D001688:Biological Products; D007376:Interleukin-2; D003208:Concanavalin A; D010844:Picibanil; D013936:Thymidine