Immunostimulants: Types and Functions

Immunomodulators are natural or synthetic materials that regulate the immune system and induce innate and adaptive defense mechanisms. These substances are classified into two types, immunostimulants and immunosuppressants. Immunostimulants can enhance body's resistance against various infections through increasing the basal levels of immune response. These agents could increase the oxidative activity of neutrophils, augment engulfment activity of phagocytic cells, and stimulate cytotoxic cells as necessary defense mechanisms. Many disorders could be treated using some immunostimulants such as autoimmune diseases, viral infections, and cancer. The researchers classified the immunostimulants using their origin and mode of action such as bacterial products, complex carbohydrates, vaccines (antigens and adjuvants), cytokines, immunoenhancing drugs, nutritional factors, animal extracts, and plant extracts. In this mini-review, the concepts, types, and functions of immunostimulants will be described as a therapeutic approach against different diseases.