Primary immune response is by which cell?

Ans. (a) B cellsRef: Robbin's pathology 9th ed. /187, 191PRIMARY IMMUNE RESPONSE* The first exposure to a foreign antigen, a lag phase occurs in which no antibody is produced, but activated B cells are differentiating into plasma cells. The lag phase can be as short as 2-3 days, but often is longer, sometimes as long as weeks or months.* The amount of antibody produced is usually relatively low.* Over time, antibody level declines to the point where it may be undetectable.* The first antibody produced is manily IgM (although small amounts of IgG are usually also produced).