In: Biology
When the chickenpox vaccine was developed older people who had not had chickenpox were among the first to be able to get the vaccine. However, sometimes people have such a minor chickenpox infection that it goes unnoticed, yet still generates complete adaptive immunity. Before giving the vaccine, healthcare workers would test potential recipients to see if they already had chickenpox and had immunity to the virus. Describe how you could develop an ELISA test to determine if someone had immunity to chickenpox. Explain the sources of antigens, antibodies, type of ELISA, and expected results for positive and negative cases.
Chicken pox is caused by Varicella virus . To check whether a person is already immuned to chickenpox or not we need to perform an ELISA test.
Foe ELISA we need antigen and antibody of Varicella virus. Now the vaccine itself contains live viruses which are weak in nature. These virus can be used as source for antigen, whereas the serum from the pateint can be used as a source of antibody. If the person is already have immunity against Varicella virus, they will have the antibody already present in the serum.
We can perform a indirect ELISA to test the presence of Varicella antibidy in the serum. briefly we need to coat the wells of the ELISA plate with Varicella antigen particle. Now, the serum samples obtained from individuals will be added to the wells. Next, if we add Varicella antibody conjugated HRP followed by substrate we will be able to detect the antigen-antibody binding in the well. If the serum of the person has already Varicella antibody present, it will form complex with the antigen. This coplex will be visualuzed with colour formation following antibody conjugated HRP and substrate addition. Wheras, if the person do not have the antibody in the seum, then in the ELISA reaciton, no colour will be developed.