This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Microbiology
Immunoglobulin present in mouth local secretions? 
Select and explain. 
A. IgA, B. IgM, C. IgG, D. IgE
A: IgA
Answer: A: IgA 
Explanation: Ans. is 'a' i.e.,IgA It is the second most abundant antibody (after IgG). It is major immunoglobulin in clostrum, saliva, tears, respiratory and gastrointestinal secretions.