DNA-BASED IMMUNIZATION AGAINST HEPATITIS-B SURFACE-ANTIGEN (HBSAG) INNORMAL AND HBSAG-TRANSGENIC MICE

Hepatitis B virus (HBV) remains a serious worldwide health problem and the possibility to control it will depend on the availability of safe , effective and affordable vaccines. Recombinant protein or plasma-der ived vaccines containing HBV surface antigen (HBsAg) are safe and gene rally efficacious, however, they are too expensive for widespread use in areas of HBV endemicity and are only partially effective for treatm ent of HBV chronic carriers. Immunization of mice by injection of HBsA g-expressing plasmid DNA results in rapid induction of strong and long -lasting humoral and cell-mediated immune responses. Here we report op timization of the humoral response with the use of necrotizing agents, co-expression of cytokines or co-stimulatory molecules and formulatio n of the DNA with cationic liposomes. DNA-based immunization of HBsAg- transgenic mice can also overcome non-response to HBsAg. Thus, DNA vac cines against HBV may be useful for both prophylactic and therapeutic purposes. (C) 1997 Elsevier Science Ltd.