Further work revealed that natural infection and the wP vaccine, but not the aP vaccine, induce B. pertussis-specific IL-17 and IFN-γ-secreting CD103+ CD44+ CD69+ CD4+ tissue resident memory T cells (TRM) that appear to play a key role in early protection of the airway mucosa from B. pertussis infection [19,22,23,24,25,26,27,28]. This evidence concerns the gene CD4 and infection.