<prompt> Which immunoglobulin is present in the breast milk: September 2005Ig AIg EIg DIg M  <response>: Ans. A: Ig A Secretory IgA is the principal immunoglobulin of breast milkcolostrum. It is synthesized in the mammary epithelial cell by the coupling of two IgA molecules, produced locally by lymphocytes resident in the breast tissue, with two proteins, J-chain and secretory component. The specificity of breast milk secretory IgA antibodies reflects the mothers exposure to mucosal infection and is independent of the specificity profile of blood-borne IgA. 