Immunoglobulin A-Mediated Protection against Bordetella pertussis Infection

Infection with Bordetella pertussis, the causative agent of pertussis (whooping cough) in humans, is followed by the production of antibodies of several isotypes, including immunoglobulin A (IgA). Little is known, however, about the role of IgA in immunity against pertussis. Therefore, we studied targeting of B. pertussis to the myeloid receptor for IgA, FcαRI (CD89), using either IgA purified from immune sera of pertussis patients or bispecific antibodies directed against B. pertussis and FcαRI (CD89 BsAb). Both IgA and CD89 BsAb facilitated FcαRI-mediated binding, phagocytosis, and bacterial killing by human polymorphonuclear leukocytes (PMNL) and PMNL originating from human FcαRI-transgenic mice. Importantly, FcαRI targeting resulted in enhanced bacterial clearance in lungs of transgenic mice. These data support the capacity of IgA to induce anti-B. pertussis effector functions via the myeloid IgA receptor, FcαRI. Increasing the amount of IgA antibodies induced by pertussis vaccines may result in higher vaccine efficacy.