Introduction
There has been a remarkable advance in the field of basic immunology during last three to four decades. Immunology is probably one of the most rapidly developing areas of medical biotechnology research and has great promises with regard to the prevention and treatment of a wide range of disorders, the inflammatory diseases of skin, gut, respiratory tract, joints and central organs. In addition, infectious diseases are now primarily considered immunological disorders, while neoplastic diseases and organ transplantation and several autoimmune diseases may involve in an immunosuppressive state . Right from the distinction between cellular and humoral arms of immunity and recognition of cell surface phenotypes on T and B cells, we have come a long way in understanding molecular mechanism of immune response and these include immunoglobulin and T cell receptor gene rearrangements, complexity of the MHC system and its role in antigen presentation and restriction of effector cytotoxic cells etc. Not only this but the immune system is also involved in the etiology as well as pathophysiologic mechanisms of many diseases . But due to many unfavourable conditions, environment and diseases it becomes weak and it needs an external source or factor which can enhance the immune response in order to fight against various diseases. Modulation of the immune responses to alleviate the diseases has been of interest for many years . So, from a therapeutic point of view immunomodulation refers to any process in which an immune response is altered to a desired level.

Definition and Scope of Immunomodulators
An immunomodulator is a substance (e. g. a drug) which has an effect on the immune system. It can be defined as a substance, which is biological or synthetic origin, having properties to modulate i e stimulate or suppress any of the components of the immune system.. In the beginning era of immunomodulation we came across the results with intralesional application of BCG and systemic use of levamisole were quite promising. Some significant progress in the field of immunomodulators is represented by the discovery of cyclosporine, it is a potent immunosuppressant that has proved to be a boon for graft rejection and also helpful in autoimmune diseases . There are two types of immunomodulators

Immunosuppressant - These agents suppress the immune response and could be used for the control of pathological immune response in autoimmune diseases, graft rejections etc.

Immunostimulants- These agents are envisaged to enhance body's resistance against infections; they enhance the basal levels of immune response, and in individuals with impairment of immune response as immunotherapeutic agent.

Medicinal plants are a rich source of substances which are claimed to induce paraimmunity, the non specific immunomodulation of essential granulocytes, macrophages, natural killer cells and complement functions. The increasing popularity in plant based medicine is now felt all over world leading to fast growing market for plant based pharmaceuticals, nutraceuticals, functional foods and even cosmaceuticals.

In all we can say that there are many great potential for the discovery of more specific immunomodulators from Indian medicinal plants.

About Author / Additional Info:
My name is Archana and presently I am pursuing M.Tech biotechnology from bhopal. I love to write articles on biotechnology and new research related to it.