Cell-mediated immunity after pertussis vaccination and after natural infection.

The aim of this study was the investigation of the specific cell-mediated (CMI) responses induced by DTaP and to compare these data to immunity after natural infection. The ability of peripheral blood T-lymphocytes to respond to the pertussis related antigens pertussis-toxin (PT), filamentous haemagglutinin (FHA), and Pertactin (PRN) was investigated in 40 children before vaccination and at different times after vaccination with DTaP (Infanrix) by measurement of antigen-specific proliferation, lymphocyte phenotype, cytokine production and expression of activation markers (CD25, HLADR). Similar investigations were performed in children 4-6 weeks after recovery from natural pertussis. DTaP created a specific T-cell-response to PT, FHA and PRN that increased continually, depending on the progress of the vaccination schedule. In contrast to waning antibody titres, CMI was stable even between the post-basic vaccination and the pre-booster period. The magnitude of CMI after DTaP equalled those after natural infection. Measurement of cytokine-pattern showed induction of IFN-tau-producing T-helper-1-cells with lower stimulation of IL 10-producing T-helper-2-cells for DTaP and natural infection. Our data indicate that DTaP-vaccination induces a potent immune response to PT, FHA, and PRN at least equivalent to CMI after natural infection. The finding of a preferential T-helper-1-induction after DTaP and natural infection suggests a role of IFN gamma-activated macrophages in the protective response against B. pertussis-induced disease.