Pertussis acellular antigens (aP)

Pertussis acellular antigens are the purified immunogenic components of the bacterium Bordetella pertussis, used as the active ingredients in acellular pertussis (aP) vaccines to prevent whooping cough. These antigens typically include pertussis toxoid (PT), filamentous hemagglutinin (FHA), pertactin (PRN), and fimbriae types 2 and 3 (FIM2/3), which are selected for their roles in bacterial virulence and their ability to elicit a protective immune response. Their primary biological function is to stimulate the host's adaptive immune system to produce specific antibodies and T-cell responses; PT-specific antibodies neutralize the systemic effects of the pertussis toxin, while antibodies against FHA, PRN, and FIM prevent bacterial attachment to the respiratory epithelium and promote pathogen clearance through opsonophagocytosis. Although acellular antigens are associated with fewer adverse effects compared to older whole-cell vaccines, they exhibit faster waning of immunity, which has contributed to the resurgence of pertussis in some populations. They are commonly administered in combination with diphtheria and tetanus toxoids (as DTaP or Tdap) to provide broad protection against these respiratory and toxin-mediated diseases.

Other names

Bordetella pertussis antigensAcellular pertussis vaccine componentsPertussis toxoidFilamentous hemagglutininPertactinFimbriae types 2 and 3

Active immunization through the induction of neutralizing and opsonizing antibodies against Bordetella pertussis virulence factors.