title: Effects of pertussis toxin on delayed-type hypersensitivity responses and on the activity of suppressor T cells on the responses.
abstract: Experiments were performed on mice to investigate the effects of pertussis toxin (PT) on delayed-type hypersensitivity (DTH) to ovalbumin (OA) and on the activity of suppressor T cells on the DTH (DTH-Ts). Mice immunized with alum-precipitated ovalbumin showed a transient DTH, which was determined as footpad swelling which disappeared 2 weeks after immunization. Maximal footpad swelling was observed 24 hr after DTH elicitation. On the other hand, when mice received PT (2 micrograms/mouse) at the time of immunization, the transient DTH became an enhanced and persistent DTH, which persisted for at least 4 weeks. In addition, the time of maximum footpad swelling was delayed from 24 to 48 hr after DTH elicitation. The immune spleen T cells from PT-treated mice showed a persistently high ability to transfer DTH into syngenic naive mice. DTH-Ts was induced in spleens of mice injected iv with OA-coupled syngeneic spleen cells. However, when these mice received PT at the time of suppressor induction, their spleen cells revealed considerably reduced suppressor activity. The activity of DTH-Ts was also reduced when DTH-Ts were either treated in vitro with PT or transferred into PT-injected recipient mice. From these results, interference with the suppressor function of DTH-Ts from PT was considered to be, at least in part, as an enhancing mechanism of DTH.
mesh_terms: D000818:Animals; D001427:Bacterial Toxins / Q000276:immunology*; D001886:Bordetella pertussis; D005260:Female; D006968:Hypersensitivity, Delayed / Q000276:immunology*; D007108:Immune Tolerance; D007116:Immunization, Passive; D051379:Mice; D037342:Pertussis Toxin; D013154:Spleen / Q000276:immunology; D050378:T-Lymphocytes, Regulatory / Q000276:immunology*; D010566:Virulence Factors, Bordetella
chemical_list: D001427:Bacterial Toxins; D010566:Virulence Factors, Bordetella; D037342:Pertussis Toxin