Sunday 21 February 2021

Antibodies qna

1. Which class of B cell receptors is expressed in naive B-cell ?

... Answer is B)
Naive B-cells have only mIgM; as they mature, they express both mIgM and mIgD.

2. Which of the following groups of antibodies can cross placenta?

... Answer is C)
Immunoglobulin G ( IgG ) is a type of antibody. Each IgG has two antigen binding sites. Representing approximately 75 % of serum antibodies in humans. IgG molecules are created and released by plasma B cells. IgG are also involved in the regulation of allergic reactions.

According to Finkelman , there are two pathways of systemic anaphylaxis : antigens can cause systemic anaphylaxis in mice through classic pathway by cross-linking IgE bound the mast cell FcεRI, stimulating the release of both histamine and platelet activating factor (PAF). In the Alternative pathway antigens form complexes with IgG, which then cross-link macrophage FcγRIII and stimulates only PAF release.

3. No antibody activity associated with

... Answer is A)
IgD activity is still unknown.

4. J chain or joining chain is found in ?

... Answer is C)
IgM is pentameric antibody molecule and IgA is dimeric antibody molecule, both of these antibodies posses J chain .

5. In the normal human being the concentration(s) of various antibodies in the serum is/are in the order

... Answer is B)
IgG is the most abundant antibody present in the serum it accounts 70-75% of total antibodies. IgA accounts 15% of total antibodies of serum. IgM account 5-10% of total antibodies of serum. IgE accounts in a normal individual are only 0.05% of total antibodies.


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