Molecular Mechanisms of <i>Bordetella </i><i>pertussis</i>-induced Immunosuppression: Effects on Cellular Homeostasis and Innate Immune Response in Children

<i>Background:</i><i> </i><i>Bordetella pertussis</i> remains a significant global health challenge, particularly in pediatric populations where the infection often leads to severe clinical outcomes. The pathogenicity of this bacterium is largely driven by its ability to secrete various virulence factors that systematically dismantle the host's primary defenses. <i>Purpose:</i><i> </i>This study aims to synthesize the pathway-level molecular mechanisms by which Pertussis Toxin (PT), Adenylate Cyclase Toxin (ACT), and Tracheal Cytotoxin (TCT) collectively subvert host immunity. By mapping these interactions, the research seeks to identify critical therapeutic targets for neutralizing toxin activity. <i>Methods:</i> Through a comprehensive mechanistic analysis and a review of current biochemical literature, we elucidate how these specific toxins disrupt essential innate immune processes. The analysis focuses on signaling cascades in leukocytes and the structural integrity of the respiratory epithelium. <i>Conclusion:</i> Our findings demonstrate that PT impairs leukocyte recruitment by ADP-ribosylating G-protein-coupled receptors (GPCRs), effectively blinding immune cells to chemotactic gradients. Simultaneously, ACT elevates intracellular cyclic AMP (cAMP) levels, thereby paralyzing phagocytic functions such as pathogen engulfment and antigen presentation, thereby blunting both innate clearance and subsequent adaptive activation. Furthermore, TCT induces direct structural damage to the respiratory epithelium via the NOD1 pathway, compromising mucosal barrier integrity and facilitating persistent bacterial colonization. Together, these toxins orchestrate a multifaceted assault that exploits the developing immune systems of children. This research concludes that understanding these molecular disruptions is vital for restoring immune competence and informs the development of next-generation mucosal vaccines, ultimately reducing the clinical burden of <i>Bordetella pertussis.</i>