Question

an immunoglobulin dimer that is concentrated in the respiratory tract is what?

Answer 1

ANSWER - IgA

IMMUNOGLOBULINS - are glycoprotein molecules that functions as antibodies,produced by plasma cells in response to an immunogen.

• Structure - basically consists of 2 identical heavy (H) chains and 2 identical light (L) chains,held together by disulfide linkages and non - covalent interactions.Thus shape is of a y - shaped tetramer- H2L2.
• Heavy chains of immunoglobulins are linked to carbohydrates,hence are glycoproteins.
• Humans have 5 classes of immunoglobulins - IgG,IgA,IgM,IgD,IgE with heavy chains - gamma,alpha,mu,delta,epsilon respectively.

IgA - monomeric in serum,dimeric with secretory component in the lumen of the gastro intestinal tract and in the respiratory tract - neutralizes toxins and microbes .

• IgA - is the most predominant antibody in the colostrum - the initial secretion from the mother's breast after a baby is born.
• IgA molecules bind with bacterial antigens present in the body surfaces (outer epithelial) and remove them,thus prevents the foreign substances from entering the body cells.