1) It is the second most abundant class containing 10-13% if serum immunoglobulins.

2) It has a half-life of 6-8 days.

3) IgA is actively secreted by mucosal associated lymphoidal tissue (MALT).

4) Its molecular weight is 60,000 Daltons.

5) IgA is synthesized locally by plasma cells and dimerized intra-cellular before secretion, with the help of cysteine rich polypeptide, called the J chain, which has a molecular weight of 15,000.IgA functions by inhibiting the adherence of coated microorganisms to the surface of mucosal cells.