Which of the following is based upon the principle of antigen - antibody interaction?

Options

A. PCR
B. ELISA
C. Recombinant DNA technology
D. RNA interference

Answer

To determine which of the following options is based on the principle of antigen-antibody interaction, we need to analyze each option provided:

1. **PCR (Polymerase Chain Reaction)**:
- PCR is a technique used to amplify specific DNA sequences. It involves the use of DNA polymerase and primers, but it does not involve any antigen-antibody interactions. Therefore, this option is not correct.

2. **ELISA (Enzyme-Linked Immunosorbent Assay)**:
- ELISA is a widely used laboratory technique that relies on the specific binding of an antigen to an antibody. In this method, an antigen is immobilized on a solid surface, and a specific antibody is added. If the antibody binds to the antigen, it indicates the presence of that antigen. This method is fundamentally based on antigen-antibody interactions. Thus, this option is correct.

3. **Recombinant DNA Technology**:
- This technology involves the manipulation of DNA to create recombinant DNA molecules. It includes techniques such as cloning and plasmid isolation. While it is a powerful tool in biotechnology, it does not involve antigen-antibody interactions. Therefore, this option is not correct.

4. **RNA Interference (RNAi)**:
- RNA interference is a biological process in which RNA molecules inhibit gene expression or translation. It is a method used to silence specific genes and does not involve antigen-antibody interactions. Thus, this option is also not correct.

After analyzing all the options, we conclude that the correct answer is **B, ELISA**, as it is the only technique that is based on the principle of antigen-antibody interaction.