Enhanced cellular immunity to hepatitis C virus nonstructural proteins by codelivery of granulocyte macrophage-colony stimulating factor gene in intramuscular DNA immunization

Hepatitis C virus (HCV) nonstructural (NS) proteins appeared to be importan t targets for HCV vaccine development, since NS-specific T-helper-cell resp onses are associated with clearance from acute HCV infection. In this repor t, we have constructed a plasmid, pTV-NS345, that encodes the HCV NS3, NS4 and NS5 proteins (NS345) and a bicistronic plasmid, PIV-NS345/GMCSF, in whi ch the HCV NS345 polyprotein and GMCSF are translated independently. Intram uscular inoculation with pTV-NS345 plasmid DNA into the Buffalo rats genera ted both antibody and T-cell proliferative responses to each NS protein. Th e expression of GMCSF, together with HCV NS345 proteins, appeared to signif icantly increase T-cell proliferative responses. In particular, the inocula tion of a bicistronic plasmid generated higher T-cell proliferative respons es to each NS protein than did the coinjection of two separate plasmids, pT V-NS345 and pTV-GMCSF. These results demonstrate that the codelivery of GMC SF augmented HCV NS345-specific cellular immunity and that the intensity of the immunity was differed depending on how GMCSF gene is codelivered. (C) 1999 Elsevier Science Ltd. All rights reserved.