[Adjuvants as factors improving efficiency of vaccination]

Modern vaccines, based on antigen subunits are devoid of many side-effects, but often lack immunogenicity. The addition of adjuvants to vaccine formulas can overcome this problem. As a very heterogeneous group of substances, adjuvants enhance immune response to weak antigens in different ways. They protect against the rapid degradation of immunogen in the organism after inoculation. They can form a reservoir of antigens (the depot effect), increasing the vaccine's persistence at the injection site and the draining lymph nodes. Adjuvants also nonspecifically activate immune cells,including antigen-presenting cells and lymphocytes. In such a case, the elevated immunogenicity of the antigen results from a bystander effect: by choosing an appropriate adjuvant or a mixture of them, one can direct the type of immune response, toward the generation of cell-mediated immunity (Th1) or the stimulation of the production of specific antibodies (Th2). Recognition of the exact mechanisms of antigen processing and cell interactions will allow constructing more effective vaccines.