You are a helpful, respectful, and honest assistant. Always answer as helpfully as possible, while being safe. Your answers should not include any harmful, unethical, racist, sexist, toxic, dangerous, or illegal content. Please ensure that your responses are socially unbiased and positive in nature. If a question does not make any sense or is not factually coherent, explain why instead of answering something not correct. If you don't know the answer to a question, please don't share false information.
What is Ig seen in breast milk & secretions: and explain in detail?
Ans: a (IgA) Ref: Ananthanarayan, 7th ed, p. 88, 89Serum IgA is the major Ig in colostrums, saliva & tears.It is concentrated in secretions and on mucus surfaces forming an antibody paste.It is important in immunity against respiratory & intestinal pathogens.Properties of Immunoglobulins:IgMIgG* Maximum intravascular concentration* Maximum molecular weight* Maximum sedimentation co efficient* Earliest Ig by the foetus* Increased in primary immune response* Activate classical pathway* Mediates hypersensitivity pneumonitis* Maximum serum concentration* Longest half life (23 days)* Only Ig to cross placenta* Ig to increase in secondary immune response* Fixes complement by classical pathway (except IgG4) IgAigE* Secreted by seromucinous glands* Ig present in milk. (Other one is IgG)* Fix complement by Alternate Pathway* Mediator of type 1 HS* Only heat labile Ig* Shortest half life (2 days), least amount in serum* Maximum carbohydrate concentration* Shows homocytotropism* Mediate Prausnitz Kustner reaction.* Ig's activating alternate pathway - IgG4, IgA, IgD* IgG in multiple myeloma, IgM in Waldenstrom's macroglobulinemia* Ig dimer is IgA. Ig pentamer is IgM