CD4 and pertussis: We evaluated the humoral and cellular immunogenicity, including lung tissue-resident memory CD4+ T cells (CD4+ TRM) and secretory IgA, of a trivalent DTaP vaccine containing three acellular pertussis antigens, PT, FHA, and PRN (developed by GC Pharma), and recombinant acellular pertussis (raP) vaccine (developed by Yonsei University and Vaccine Innovative Technology ALliance (VITAL), Korea), which was produced from E. coli.