Complex sentence: Two toxins, known as the pertussis toxin (or PTx) and adenylate cyclase (CyaA), cause phagocytes to convert too much ATP to cyclic AMP, which can cause disturbances in cellular signaling mechanisms, and prevent phagocytes from correctly responding to an infection.
Split into simpler sentences: Two toxins, known as the pertussis toxin (or PTx) and adenylate cyclase (CyaA), are responsible for this inhibition. The end result is that phagocytes convert too much ATP to cyclic AMP, which can cause disturbances in cellular signaling mechanisms, and prevent phagocytes from correctly responding to an infection.