PATHOLOGY

Detailed explanation-1: -Immunoglobulin A (IgA): It’s found in the linings of the respiratory tract and digestive system, as well as in saliva (spit), tears, and breast milk.

Detailed explanation-2: -Although all three major classes of immunoglobulins are present in human colostrum and milk, only IgA and IgM are locally produced in the human mammary gland. These immunoglobulins protect neonates and infants against infection, particularly IgA protects against respiratory tract and gastrointestinal infections.

Detailed explanation-3: -IgA is the main class of antibody found in many body secretions, including tears, saliva, respiratory and intestinal secretions, and colostrum (the first milk produced by lactating mothers). Very little IgA is present in the serum.

Detailed explanation-4: -Secretory IgA (SIgA) is present in mucosal secretions, including milk, saliva, tears, intestinal, and cervical fluids. SIgA and can be structurally classified as a homodimer, joined by a polypeptide (J chain); both components are produced by plasma cells in the lamina propria of mucosal surfaces.

Detailed explanation-5: -A large part of immunoglobulins excreted in milk are IgA that protect mainly against enteric infections. The specificity of maternal milk IgA is driven by an entero-mammary cell circulation. Human milk also contains anti-idiotypic antibodies capable of enhancing infant antibody response.