Acellular pertussis booster in adolescents induces Th1 and memory CD8+ T cell immune response.

In a number of countries, whole cell pertussis vaccines (wcP) were
replaced by acellular vaccines (aP) due to an improved
reactogenicity profile. Pertussis immunization leads to specific
antibody production with the help of CD4(+) T cells. In earlier
studies in infants and young children, wcP vaccines selectively
induced a Th1 dominated immune response, whereas aP vaccines led to
a Th2 biased response. To obtain data on Th1 or Th2 dominance of
the immune response in adolescents receiving an aP booster
immunization after a wcP or aP primary immunization, we analyzed
the concentration of Th1 (IL-2, TNF-α, INF-γ) and Th2 (IL-4, IL-5,
IL-10) cytokines in supernatants of lymphocyte cultures
specifically stimulated with pertussis antigens. We also
investigated the presence of cytotoxic T cell responses against the
facultative intracellular bacterium Bordetella pertussis by
quantifying pertussis-specific CD8(+) T cell activation following
the aP booster immunization. Here we show that the adolescent aP
booster vaccination predominantly leads to a Th1 immune response
based on IFNgamma secretion upon stimulation with pertussis
antigen, irrespective of a prior whole cell or acellular primary
vaccination. The vaccination also induces an increase in peripheral
CD8(+)CD69(+) activated pertussis-specific memory T cells four
weeks after vaccination. The Th1 bias of this immune response could
play a role for the decreased local reactogenicity of this
adolescent aP booster immunization when compared to the preceding
childhood acellular pertussis booster. Pertussis-specific CD8(+)
memory T cells may contribute to protection against clinical
pertussis.