This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Immunology, Subject name: Microbiology
[{'content': 'The secretory component of immunoglobulin molecule is - \nSelect and explain. \nA. Formed by epithelial cells of lining mucosa, B. Formed by plasma cell, C. Formed by epithelial cell and plasma cell, D. Secreted by bone marrow', 'role': 'user'}, {'content': 'Answer: C \nExplanation: The secretory component is a component of immunoglobulin A (IgA). Secretory component is a proteolytic cleavage product of the polymeric immunoglobulin receptor which remains associated with dimeric IgA in sero-mucus secretions. Polymeric IgA binds to the polymeric immunoglobulin receptor on the basolateral surface of epithelial cells and is taken up into the cell transcytosis. Ref: Ananthanarayan & Panikers textbook of microbiology 9th edition pg:97', 'role': 'assistant'}]