Secreted by plasma cells, the main function of antibodies, also known as immunoglobulins, is to counter antigens like viruses and bacteria. The ability of antibodies to bind to antigens has led to their use in a very large number of applications in medical and life sciences. Antigens are mainly classified in two ways, monoclonal and polyclonal, depending on the manner they are created from lymphocytes. A quick look into the difference between the two and their roles:
The Difference in Production
Polyclonal antibodies (pAbs) are produced by different B cell clones and thus the mixture is typically heterogeneous. They can identify and bind to several different epitopes of the same antigen. Polyclonal antibodies are produced by injecting animals with an immunogen.
Monoclonal antibodies (mAbs) are produced by Identical B cells and clones of the same parent cell. This gives them only a monovalent affinity and the capability to identify only the same epitope of an antigen. Monoclonal antibodies are produced using tissue culture techniques. The process begins with the repeated injection of the specified antigen into a target animal. The B-lymphocytes are removed from the spleen of the animal after it develops an immune response. Fusing the B- lymphocytes with a line of myeloma cell creates B cell-myeloma hybridomas, which can continuously grow in culture to produce antibodies that can then be screened to obtain the desired mAb.
Advantages and Disadvantages of Polyclonal Antibodies
Both the production time and the cost of production are low, according to https://www.pacificimmunology.com.The polyclonal antibodies from Mybiosource.com are extremely stable and can well tolerate any changes in the pH or buffer. They possess a high affinity making them ideal for chromatin immunoprecipitation. They also tolerate better any changes in the antigen. The disadvantages include a higher variability between batches and more checking required for cross-reactivity.
Advantages and Disadvantages of Monoclonal Antibodies
They permit highly specific recognition of a single epitope of an antigen and since the hybridoma cell lines are immortal, an unlimited quantity of the antibodies can be produced. Not only do they achieve high consistency between experiments but they also have very little cross-reactivity and background noise. Monoclonal antibodies are very good for affinity purification. Among the disadvantages of monoclonal antibodies is a long time taken to develop it. Further, the process requires a high degree of technical skills. While a large amount of specific antibodies can be produced, they can often be too specific to detect across a wide species range. Monoclonal antibodies are also sensitive to changes in the epitope that can result in the binding capacity reducing dramatically its binding capacity.
Whether a polyclonal or monoclonal antibody is better depends on the circumstances of their use. Due to their ability to recognize different target molecule epitopes, polyclonal antibodies make ideal reagents for the detection of unknown antigens. Polyclonal antibodies are used in several immunoassays like ELISA, immunohistochemistry, microarray assays, etc. as a secondary antibody to amplify the signal and make possible better detection. On the other hand, monoclonal antibodies provide a source of antibodies that is virtually unlimited and since they are homogenous, their behavior is predictable. They are typically used as primary antibodies in assays.