ANATOMY

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: -Breast milk provides the first source of antibody-mediated immune protection in the intestinal tract of suckling infants, in the form of secretory IgA (SIgA) (1). IgA produced by plasma cells in the mammary gland is transported across alveolar epithelial cells (ECs) by the polymeric Ig receptor (pIgR).

Detailed explanation-3: -IgA antibodies were found in the tears of all 15 subjects, although S. mutans is a nonocular bacterium. The IgA antibody levels in tears and saliva were not significantly different.

Detailed explanation-4: -Two major antibody classes operate in saliva: secretory IgA (SIgA) and IgG. The former is synthesized as dimeric IgA by plasma cells (PCs) in salivary glands and is exported by the polymeric Ig receptor (pIgR). Most IgG in saliva is derived from serum (mainly via gingival crevices), although some is locally produced.

Detailed explanation-5: -Immunoglobulin A (IgA) is an antibody that’s part of your immune system. IgA is found in mucous membranes, especially in the respiratory and digetive tracts. It is also found in saliva, tears, and breastmilk.