Paper I
Question
What is mucosal immunity.
Answer
Mucosal immunity is the specialized arm of the immune system protecting mucosal surfaces (respiratory, gastrointestinal, genitourinary tracts) — the body’s largest area of contact with the external environment — mediated principally by secretory IgA, produced by plasma cells in the mucosal lamina propria and transported across epithelial cells into secretions, where it acts by immune exclusion, binding and agglutinating pathogens/toxins at the mucosal surface to prevent adherence and invasion, without requiring complement activation or inflammation.