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A group of mice was aerosol infected with live, virulent Bordetela pertussis bacteria. During a period of 7 weeks following the infection, with intervals of 1 week, lymphocytes were isolated from the tracheobroncheal lymph nodes (TBL) and the spleens (SPL) of the infected mice. The in vitro proliferative responses as well as the gamma interferon and tumor necrosis factor production levels of the isolated lymphocytes in response to stimulation with whole killed B. pertussis bacteria were measured as parameters for cell-mediated immunity (CMI). The course of the infection was monitored by counting of CFU in the lungs of the mice. Moreover, antibody responses in serum against a range of B. pertussis antigens were assessed. The results showed that a vigorous proliferative response of the TBL and SPL to stimulation with whole killed B. pertussis bacteria was induced by the infection. The proliferative response of the TBL was significantly higher than the response of the SPL. The proliferative responses were maximal 3 to 4 weeks after the infection and were paralleled by in vitro gamma interferon and tumor necrosis factor production upon specific stimulation. The development of the CMI was observed simultaneously with the clearance of the infection from the lungs. Antibody responses became measurable in the sera only after the infection was cleared. A specific CMI against pertussis toxin, the filamentous hemagglutinin, the 69-kDa outer membrane protein, and the agglutinogens 2 and 3, antigens which are under consideration for inclusion in future acellular pertussis vaccines, was successfully demonstrated in mice 3 weeks after the infection.on August 1, 2020 by guest http://iai.asm.org/ Downloaded from

Ten adult humans were vaccinated with the Japanese acellular pertussis vaccine JNIH-3, containing detoxified pertussis toxin (PT), formaldehyde, and filamentous hemagglutinin. The vaccination induced a specific antibody response to PT and filamentous hemagglutinin, and a Western blot (immunoblot) analysis of the antibody response to PT revealed antibodies to PT subunits Si, S2, S3, S4, and S5. The response of peripheral lymphocytes to PT was assessed in an in vitro proliferation assay. A proliferative response to detoxified PT and PT dimers S2-S4 and S3-S4 was found, and it was further demonstrated that the proliferative response to detoxified PT and dimer S2-S4 was mediated by T cells of the CD4+ phenotype. The specificity of the proliferative response to subunit S4 was analyzed with a range of synthetic peptides synthesized on the basis of the primary sequence of subunit S4. The proliferative response to the peptides revealed two major and one minor T-cell epitope located in the NH2-terminal end of subunit S4. Pertussis toxin (PT) is considered one of the main virulence factors produced by Bordetella pertussis (52). Active or passive immunization with PT is protective in humans against disease and in animal models against lethal infection with virulent B. pertussis (1, 33, 44). Toxoided forms of PT are the principal components of acellular pertussis vaccines currently in use or under development (41). PT, which is composed of five subunits, termed S1 through S5, exhibits

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