These toxins are required for efficient airway colonization in immunocompetent mice particularly in the early phases of infection, where the CyaA and PT toxin activities interfere with the TLR signaling-activated chemoattraction and bactericidal activity of sentinel phagocytes, inhibiting also the production of antimicrobial peptides by epithelial cells and enabling bacterial proliferation on the nasopharyngeal mucosa [60,62,83,84]. This evidence concerns the gene F2 and infection.