Fc receptor-mediated immunity against Bordetella pertussis

The relevance of specific Abs for the induction of cellular effector functi ons against Bordetella pertussis was studied. IgG-opsonized B. pertussis wa s efficiently phagocytosed. by human polymorphonuclear leukocytes (PMN). Th is process was mediated by the PMN IgG receptors, Fc gamma RIIa (CD32) and Fc gamma RIIIb (CD16), working synergistically. Furthermore, these Fc gamma R triggered efficient PMN respiratory burst activity and mediated transfer of B. pertussis to lysosomal compartments, ultimately resulting in reduced bacterial viability. Bacteria opsonized with IgA triggered similar PMN acti vation via Fc gamma alphaR (CD89). Simultaneous engagement of Fc alpha R1 a nd Fc gammaR by B. pertussis resulted in increased phagocytosis rates, comp ared with responses induced by either isotype alone. These data provide new insights into host immune mechanisms against B. pertussis and document a c rucial role for Ig-FcR interactions in immunity to this human pathogen.