Answer:
IgM
Explanation:
The first molecular mechanism of adptative immunity to appear is IgM. These molecular pentameric (constituted of 5 smaller units), are produced in the macrophages of the organism and are released when some time has elapsed since the beginning of the infection (latency period). By having 5 possible epitopes, it increases the chances of triggering a cell-mediated immune response and stimulating the production of IgG.
