Question

Antibodies present in colostrum which protect the new born from certain diseases is of
A. IgG type
B. IgA type
C. IgD type
D. IgE type

Answer 1

Hint: Immunoglobulin known as antibodies. It is a glycoprotein molecule produced by plasma cells (WBC). They generally act as an immune response and binding to particular antigens such as bacteria, viruses, and foreign substances aiding in their destruction. Ig occurs in two main forms: soluble antibodies and membrane-bound antibodies.

Complete answer:
Option A IgG: Immunoglobulin G is a type of antibody. IgG is the most common type of antibody found in blood circulation in the human serum, $$75\mathrm{\%}$$ of serum antibodies. Immunoglobulin G molecules are secreted and released by plasma B cells. Each IgG antibody has two paratopes.
Option A is not correct.
Option B IgA: Antibodies present in colostrum is IgA which is known as secretory immunoglobulin. It is found in the mucosal lining of the gastro-intestinal tract, urino-genital tract and the respiratory system. Its action is to prevent pathogenic infections.
So, option B is correct.
Option C IgD: Immunoglobulin D is a unique antibody with a low concentration in serum. IgD is found on the surface of B lymphocytes where its role as a receptor for antigen.
So, option C is not correct.
Option D IgE: Immunoglobulin E is a type of antibody that has been found only in mammals. These antibodies are mainly found in the mucous membranes, skin, and lungs. They cause the body to react against antigens such as pollen, fungus spores, and animal dander.
So, option D is not correct.

Hence, Option B is the correct answer.

Note:
IgA is the most important antibody which can be found in many body secretions such as respiratory and intestinal secretions, tears, saliva, and colostrum (the first milk produced by lactating mothers). The early milk is primarily rich in antibodies particularly IgA but also some IgM and IgG. During the first few days of life the new-borns can get these kinds of proteins intact from the digestive tract directly into the bloodstream.