Antibodies are part of defense system to protect the body against the invading foreign substances namely the antigen.
In response to an antigen invasion the immune system (defense mechanism of the body) produce different types of antibodies. These types of antibodies which can react with the same antigen are designated as polyclonal antibodies.
Monoclonal Antibody is a single type of antibody that is directed against a specific antigenic determinant.
The method of production of monoclonal antibodies by in laboratory (invitro) techniques has paved the way for current clinical research. This is being currently used in both diagnostic and medical approaches. It has been widely used in the branch of biological science, biochemistry and tumor imaging. In the field of medicine, the place of monoclonal antibodies particularly regarding patient care is considered very important.
Another group of monoclonals that react with tumour associated antigens are murine monoclonal antibodies which do so against some antigens found in cancer cell membranes, breast cancer, brain tumour, ovarian carcinoma etc. Efficacy has been achieved in some of the clinical trials conducted with the use of those antibodies.
Potentially monoclonal antibodies have been widely used to modify or control the aberrant behaviour of some cells of the immune system and in autoimmune disorders.
Another most dramatic application of monoclonal antibodies is in the field of imaging. Deep lesions in certain tissues or the localization of tumour which cannot be detected by diagnostic tests can be easily detected through imaging tests. Radio labelled antibody imaging has been proved successful in studies on animals for malignant and non-malignant lesions. Some useful monoclonal antibodies have been produced for invitro studies directed against melanoma associated antigens. Breast cancer is also detected through imaging techniques.
In the recent years for the efficient localization of cytotoxic treatment, great benefits have been derived from the use of monoclonal antibodies as carriers of drugs or toxins. Also, when monoclonal antibodies were coupled to bacterial or plant toxins for e.g. Exotoxin A of pseudomonas aeruginosa or abrin from Abrus precatorious penetrates the cell membrane and inhibits protein synthesis. These antibodies have high potential to kill the tumour cells even when the antigenic determinant which is specific for monoclonal carriers is not expressed in high density at the cell surface. The high nature of selectivity by monoclonal antibodies allows such toxin conjugates to kill selected cells in mixed populations. The use of these monoclonal antibodies linked with drug has been proved to be effective in preclinical studies. But the treatment in humans is yet to be proved and its experience is limited and is based on laboratory studies with cultured cells as targets.
In the field of Microbiology, numerous murine monoclonals have been produced against a variety of microbial antigens including many of the medicinally important viruses, bacteria and parasites. Also, antibodies have been produced against membrane components, toxins and other selected target molecules. Interferon was the first molecule to be purified using murine monoclonals. Some of the diagnostic materials for meningococci, and Chlamydia are monoclonals. This has resulted in the specificity compared with other existing antibodies. The application of monoclonal antibodies to many assays and purification procedures has also increased. Several diagnostic tests that use monoclonal antibodies for many important molecules like fibrinogen, alkaline phosphatase and complement proteins etc. are in demand.
Further researches are going on with the preliminary trials of human monoclonal antibodies directed against endotoxins of gram negative bacteria. These trials will be helpful in the future to find solutions for many therapeutic problems including antibiotic resistance, infections etc.
These new developments in antibody technology are making a great impact in the field of clinical research for the well being of human subjects.