Immunology and Cell Biology

Lung Immunology

The lungs are usually the first site of exposure to pathogens. To counter this imminent threat, the lungs have their own large and complex system of cells of the immune system. The alveoli are the terminal branches of the lungs where the majority of gaseous exchange occurs. As such it only houses a small number of immune cells that in mouse and man are comprised almost entirely of alveolar macrophages. These macrophages secrete a plethora of anti-microbials including oxygen metabolites, lysozyme, antimicrobial peptides and proteases. They also phagocytose and kill microbes. Alveolar macrophages are important for the recruitment of other immune cells when the threat is great by secretion of cytokines and chemokines.They can also process and present antigens to helper and cytotoxic T cells. Knowledge of pulmonary immunology is essential to the understanding of certain respiratory diseases.