Use your understanding of direct and indirect ELISA to answer the following questions

a. Suppose you work in a clinical lab and are responsible for screening a large array of samples for the presence of gonadotropin (a positive indicator of pregnancy). Which one of the two types of ELISA would be the best approach for this purpose?
b. Suppose you are working with ribonuclease A (RNase A) in the laboratory and that you produce a panel of mouse monoclonal antibodies to RNase A as part of your work. Your next step is to determine which of your monoclonal antibodies is able to recognize RNase A the best. Would you use indirect ELISA or sandwich ELISA for this? You should assume that no other lab has monoclonal antibodies to RNase A (that's why you're trying to make them in the first place!). You may assume that you have significant amounts of RNase A at a known concentration.

Please give good answers with explanations.

Indirect ELISA will be the best approach to test the gonadotropin according to example.

Explanation:

Now, the scenario is that we are working on ribonuclease A (RNase A) which is an antigen and against this we produced mouse monoclonal antibodies to RNase A (anti-RNase A).

Note: No other laboratories have these monoclonal antibodies.

So, it means we don't have commercially available antibodies against RNase A and we are producing antibodies.

According to this scenario we will use indirect ELISA because firstly, we use antigen (RNase A) and then monoclonal antibodies against RNase A and after that we will use anti-monoclonal RNase A antibodies (secondary antibodies) with substrate to produce color according to concentration of antibodies.

Note: Secondary antibodies (anti-monoclonal RNase A antibodies) can be produced against RNase A antibodies.

We can't use sandwich ELISA because there is not any lab who has monoclonal antibodies against RNase A. So, first we use antigen then its antibodies and then against these antibodies we use secondary antibodies to determine the effectiveness of monoclonal antibodies against RNase A.