Studies on mice showed that chitosan as an adjuvant for H5 inactivated influenza vaccines administered intramuscularly enhances significantly antibody titers and protective efficiency not only against homologous influenza viruses, but also against drift variants. Chitosan adjuvanted vaccines induced high antibody titers after a single immunization and with a low dose of antigen. High antibody titers remained for at least 6 months. Chitosan adjuvanted vaccine stored at 4 degrees C preserves its adjuvant properties for at least 8 months. Chitosan stimulates proliferative and cytotoxic activity of splenic mononuclear leukocytes in mice and promotes an increase in the numbers of CD3, CD3/NK, I-AK (MHC II), and H-2Db (MHC I) cells. After intramuscular immunization, chitosan did not induce IgE antibodies and antibodies against chitosan itself. Chitosan is a promising adjuvant candidate for inactivated influenza vaccines administered parenterally.
A number of preclinical and clinical studies with chitosan-adjuvanted antigen- and DNA-based vaccines have been carried out. Various chitosans and their modifications, in different forms (solutions, powders, gels and particles), have been evaluated with various antigens administered via different routes. Chitosan is a generic name for a wide array of glucosamine-based substances derived from biological sources, and standardization is necessary. However, in most of the studies published to date, molecular weight, viscosity, deacetylation degree and/or purity level (especially endotoxins) are not provided for the initial chitosan substance and/or final formulation and the preparation procedure is not detailed. Evaluation of adjuvant properties is challenging, given that the only available data are insufficient to demonstrate immunogenicity for chitosans with characteristics within certain intervals to elucidate mechanisms of action or to exclude impurities as the active substance. These and other issues of chitosan-based vaccine adjuvants are summarized and a step-by-step evaluation approach for chitosan-based vaccine adjuvants is outlined.
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Vaccines are the cornerstone of infectious disease control and prevention. The outbreak of SARS-CoV-2 has confirmed the urgent need for a new approach to the design of novel vaccines. Plant viruses and their derivatives are being used increasingly for the development of new medical and biotechnological applications, and this is reflected in a number of preclinical and clinical studies. Plant viruses have a unique combination of features (biosafety, low reactogenicity, inexpensiveness and ease of production, etc.), which determine their potential. This review presents the latest data on the use of plant viruses with different types of symmetry as vaccine components and adjuvants in cancer immunotherapy. The discussion concludes that the most promising approaches might be those that use structurally modified plant viruses (spherical particles) obtained from the Tobacco mosaic virus. These particles combine high adsorption properties (as a carrier) with strong immunogenicity, as has been confirmed using various antigens in animal models. According to current research, it is evident that plant viruses have great potential for application in the development of vaccines and in cancer immunotherapy.
Modern possibilities of refractometry allow us to consider this technique as promising in terms of use in dental practice for the diagnosis of herpetic infection of the oral cavity. The method will speed up and simplify the process of diagnosing the disease, which, in turn, will improve the quality of the treatment.
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