The pertussis toxin primarily affects the respiratory tract by paralyzing the cilia, the tiny hair-like structures that help clear mucus and debris from the lungs. This leads to the accumulation of mucus, causing the characteristic severe coughing fits of whooping cough. Additionally, the systemic action of pertussis toxin can lead to lymphocytosis, an increase in white blood cells, which is a hallmark of the infection. The adenylate cyclase toxin further weakens the immune response by inhibiting the function of phagocytic cells, such as neutrophils and macrophages, thereby facilitating the persistence of the bacteria within the host.
