Purpose and importance of the blocking step during ELISPOT a

Purpose and importance of the blocking step during ELISPOT assay?

What results would one expecte if this step had been omitted?

Solution

Answer:

ELISPOT is Enzyme-linked immunospot assay used widely for monitoring immune responses. It is a very sensitive technique and works as long as the protein is released and the specific antibody is present.

In ELISPOT, blocking step is performed by the addition of 100 µl per well 2% dry skim milk at room temperature for two hours. This step is important to block non specific sites and preventing non specific binding to the PVDF membrane used for the assay.

If the blocking step is omitted, it can give rise non specific signals (spots) and artifacts in the results.