Advances in DNA immunization against hepatitis C virus infection.

Hepatitis C virus (HCV) causes chronic infection in approximately two thirds of cases, leading to chronic hepatitis, liver cirrhosis and hepatocellular carcinoma in a substantial proportion of the 170 million HCV-infected individuals worldwide. As there is neither prophylactic nor therapeutic vaccines for this virus, the research in this area is of special importance. Several vaccine candidates have been evaluated in pre-clinic, but only a few have reached the clinical evaluation. DNA immunization is one of the most evaluated approaches to obtain an effective vaccine against HCV infection. In the last few years a group of technical refinements in DNA vaccines has allowed to increase their immunogenicity. Two DNA vaccine candidates against HCV have already reached clinical evaluation, and are well tolerated and immunogenic in HCV-chronically infected individuals. The main results, opportunities and challenges of DNA immunization against HCV are discussed further in the present commentary. DNA vaccination is already a valuable tool for research HCV. Further improvements in formulation and delivery devices might be sufficient for becoming a real alternative in HCV vaccine.