Specific immune response in adult medical personnel immunized with acellular pertussis vaccine with special emphasis on T helper cell response

Recent epidemiologic data have indicated that adults are the most important reservoir that transmit pertussis to children. However conventional whole cell pertussis vaccine is contraindicated in adults and children over 7 years of age because of the unacceptably high rate of adverse reactions. The aim of this study is to evaluate the specific cellular immune responses and adverse reactions to a less reactogenic acellular pertussis vaccine in adult volunteers. Eighty healthy medical personnel in Chang Gung Children's Hospital were enrolled. Volunteers in each group received: (1) Td + full strength acellular pertussis vaccine (PT, 1 μg/0.5 ml; FHA, 4 μg/0.5 ml); (2) Td + half strength acellular pertussis vaccine; (3) Td alone. Lymphocyte phenotypic analysis, antigen-specific antibody titers, antigen-specific proliferative response and cytokine levels were evaluated before and 1 month after vaccination. Our data revealed: (I) the adverse reactions were minimal; (2) phenotypic analysis showed no non-specific activation of helper T or memory T cell after vaccination; (3) both PT and FHA-specific antibody titers increased significantly after vaccination; (4) PT antigens had a mitogenic effect on cold blood mononuclear cells and peripheral blood mononuclear cells of the adult volunteers; (5) FHA-specific T cell proliferative responses significantly increased after vaccination; (6) the cytokine production pattern showed predominant activation of Th 1 cells as reflected in increased production of γ-IFN after vaccination. Acellular pertussis vaccine can effectively induce both humoral and cellular immune response in adults.