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
Which of the following immunoglobulin mediates primary immune response September 2011 
Select and explain. 
A. IgA, B. IgM, C. IgG, D. IgD
B: IgM
Answer: B: IgM 
Explanation: Ans. B: IgM The antibody formed in the primary response is predominantly IgM and in the secondary response IgG