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
First antibody response is mediated by - 
Select and explain. 
A. IgE, B. IgM, C. IgA, D. IgD
B: IgM
Answer: B: IgM 
Explanation: IgM antibodies appear early in the course of an infection and usually reappear, to a lesser extent, after fuher exposure. Ref: Ananthanarayan & Panikers textbook of microbiology 9th edition pg:98