IgA is also found in which secretion besides saliva and tears?

IgA is also found in which secretion besides saliva and tears?

• A. Breast milk
• B. Urine
• C. Gastric juice
• D. Cerebrospinal fluid

Answer: (A)

IgA is the main antibody type that protects mucosal surfaces and is secreted into many body secretions as secretory IgA. In breast milk, secretory IgA is abundant and carries a secretory component that protects it from digestion, allowing it to function in the infant’s gut. There it neutralizes pathogens and prevents their attachment to the intestinal mucosa, providing passive protection during early life when the newborn’s immune system is still developing. Urine and cerebrospinal fluid do not routinely contain significant IgA, and gastric juice is not a major source of antibodies. Thus, breast milk is the secretion that naturally contains IgA.

IgA is the main antibody type that protects mucosal surfaces and is secreted into many body secretions as secretory IgA. In breast milk, secretory IgA is abundant and carries a secretory component that protects it from digestion, allowing it to function in the infant’s gut. There it neutralizes pathogens and prevents their attachment to the intestinal mucosa, providing passive protection during early life when the newborn’s immune system is still developing.

Urine and cerebrospinal fluid do not routinely contain significant IgA, and gastric juice is not a major source of antibodies. Thus, breast milk is the secretion that naturally contains IgA.