Question

Monoclonal antibodies are preferred over polyclonal antibodies for diagnostics and antibody based therapy? Justify giving two reasons for the same by taking Herceptin as an example.

Answer 1

Monoclonal antibodies (mAbs) are preferred over polyclonal antibodies (pAbs) for diagnostics and antibody-based therapy due to the following reasons:

1. Specificity: Monoclonal antibodies recognize a single epitope on an antigen, while polyclonal antibodies recognize multiple epitopes. This makes monoclonal antibodies highly specific and eliminates the possibility of cross-reactivity with other proteins, leading to accurate diagnosis and effective therapy.
2. Consistency: Monoclonal antibodies are produced by a single clone of B cells and are therefore highly consistent in terms of their structure, affinity, and specificity. On the other hand, polyclonal antibodies are produced by multiple clones of B cells and vary in their specificity, affinity, and structure, which can lead to batch-to-batch variations.

Taking the example of Herceptin, which is a monoclonal antibody used for the treatment of HER2-positive breast cancer, the advantages of using mAbs over pAbs can be further elucidated. Herceptin specifically targets the HER2 protein, which is overexpressed in certain breast cancer cells. Using a monoclonal antibody like Herceptin ensures that only the HER2 protein is targeted, reducing the risk of off-target effects. Moreover, Herceptin has a high binding affinity to HER2, which leads to effective inhibition of the protein's function, resulting in tumor cell death. The specificity and consistency of Herceptin make it a highly effective therapy for HER2-positive breast cancer patients.