Question

IgA provides passive immunity through what mechanism, particularly via colostrum and breast milk?

Options

• Activating complement proteins

• Crossing the placenta before birth

• Secretory protection through maternal secretions

• Triggering allergic reactions

Answer 1

IgA provides secretory protection through passive immunity transfer via colostrum and breast milk. These maternal secretions contain high concentrations of IgA, which protect the infant's mucosal surfaces (gastrointestinal and respiratory tracts) from pathogens during early life when their own immune system is still developing.