Thursday, 7 January 2016

Latest Immunology Interview Questions and Answers

41. What is immuno fluorescence?
Fluorescence is the property of absorbing light ray of particular wavelength and emitting rays in different wavelength.
Antigens that are bound to cells or tissue sections can be visualized by tugging the antibody molecule with a fluorescent dye or fluorochrome.

42. What is counter current immuno electrophoresis?
This technique involves the simultaneous electrophoresis of antigen and antibody in the gel in the opposite direction resulting in precipitation of point where there is optimum concentration of antigen-antibody.
This method produces visible precipitin with in 30 minutes and is 10 times more sensitive than the standard double diffusion technique.

43. Give some applications of immuno electrophoresis.
1.    This technique is useful for testing normal and abnormal proteins in serum and urine.
2.    It is useful to determine whether a patient produces abnormally a low amount of one or more proteins.
3.    It is also used if a patient over produces some serum proteins.

44. How is immuno electrophoresis more advance than paper electrophoresis?
In paper electrophoresis, serum proteins can be separated into 5 different bands but the same protein using immuno electrophoresis can be separated into 30 different proteins.

45. What is immuno electrophoresis?
The resolving power of immuno diffusion was greatly enhanced bye immuno electrophoresis. This involves the electrophoretic separation of antigen into its constituent proteins followed by immuno diffusion.
This technique is performed on 1% agarose gel. Antigen mixture is first electrophori zed and separated based on charge, troughs are then cut in the agarose gel, and antiserum is added to the troughs.
The agarose gel is then incubated 18-24hrs during which the antigen and antibody diffuse towards each other. The formation of precipitin bands can be observed for the individual antigen components.

46. What is double immuno diffusion method?
In this method, both antigens and antibodies diffuse radically from wells towards each other by establishing a concentration gradient. As equivalence is reached, a visible line of precipitation is observed.
The patterns of precipitin lines that are formed when two different antigens are placed in adjacent wells indicate whether they share any common epitope or not.
Identity occurs when two antigens share identical epitopes; hence, the line of precipitation formed by them will fuse to give single curve line of identity.
Non-identity occurs when two antigens are unrelated. The antiserum form independent precipitin lines that cross each other.
Partial identity occurs when two antigens share common epitope. The antiserum forms line of identity with the common epitope and a curved spur with the unique epitope.

47. What is the limitation for radial immuno diffusion method?
This method cannot the antigens present in concentration below 5-10 micro grams/ml.

48. What is radial immuno diffusion method?
It is used to qualitate the antigen. Suitable dilution of antiserum is incorporated in the agar gel. Antigen is added to the wells cut on the surface of the gel. As the antigen diffuses into the agar region, equivalence is established and ring of precipitation is formed. The area of precipitin ring is directly proportional to the concentration of antigen. By comparing the area of precipitin with a standard curve obtained by measuring the precipitin area of known concentration of antigen, the concentration of antigen in the given sample can be determined.

49. Name the two-immuno diffusion techniques.
•    Radial immuno diffusion method and
•    Double immuno diffusion in two dimensions

50. What are immuno diffusion reactions?
These reactions can be used to determine relative concentrations of antigens and antibodies to compare antigens and to determine the relative purity of an antigen. They are mainly preformed in 1% agarose gels.

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