2. What are the advantages of using a peptide marker instead of a full length antigen in immunodiagnosis?

Question

2. What are the advantages of using a peptide marker instead of a full length antigen in immunodiagnosis?

Answer 1

I assume you are comparing injection of the a full length antigen versus a peptide into the bunny for antibody production.  Use of the peptide gives you much more specificity.  The peptide can be chosen from a sequence common to diverse members of a family of proteins and hence recognize these proteins with equal affinity.  Conversely, the peptide could be chosen to be selective for one or a subset of related proteins and hence would not report on levels of the proteins of no interest.  On the other hand, use of the full length antigen is more likely to give you a higher antibody titre and this is a cheaper alternative if the antibody is to be used in more qualitative tests.