DNA immunization efficiently targets conserved functional domains of protease and ATPase/helicase of nonstructural 3 protein (NS3) of human hepatitis C virus

• Published in: Immunology letters Vol. 88; no. 1; pp. 1 - 13
• Main Authors: Isaguliants, Maria G, Petrakova, Natalia V, Mokhonov, Vladislav V, Pokrovskaya, Katja, Suzdaltzeva, Yulia G, Krivonos, Alexander V, Zaberezhny, Alexei D, Garaev, Mansur M, Smirnov, Valeri D, Nordenfelt, Erik
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 03-07-2003
• Subjects: Adenosine Triphosphatases - chemistry; Adenosine Triphosphatases - genetics; Adenosine Triphosphatases - immunology; Amino Acid Sequence; Animals; Antibody Specificity; Conserved Sequence; Cytokines - biosynthesis; DNA Helicases - chemistry; DNA Helicases - genetics; DNA Helicases - immunology; DNA immunization; Epitopes; Functional domains; HCV; Hepatitis C Antibodies - blood; Hepatitis C Antibodies - immunology; Hepatitis C, Chronic - immunology; Humans; Immunization; Lymphocyte Activation; Medicin och hälsovetenskap; Mice; Mice, Inbred C57BL; Molecular Sequence Data; Nonstructural protein 3; Protein Structure, Tertiary; Rabbits; Recombinant Proteins - chemistry; Recombinant Proteins - genetics; Recombinant Proteins - immunology; Sequence Alignment; Serine Endopeptidases - chemistry; Serine Endopeptidases - genetics; Serine Endopeptidases - immunology; T-Lymphocytes - immunology; Vaccines, DNA - immunology; Viral Nonstructural Proteins - chemistry; Viral Nonstructural Proteins - genetics; Viral Nonstructural Proteins - immunology; Functional domains; OD, optical density; Epitopes; NS3, nonstructural protein 3 of HCV; HPV16, human papilloma virus type 16; SI, stimulation index; CMVIE, cytomegalovirus immediate early promoter; Nonstructural protein 3; DNA immunization; HCV, human hepatitis C virus; ns1–18, synthetic peptides from NS3; ConA, conconavalin A; SD, standard deviation; HCV; aa, amino acid
• ISSN: 0165-2478; 1879-0542
• DOI: 10.1016/S0165-2478(03)00051-8

Nonstructural protein 3 (NS3) of human hepatitis C virus (HCV) is a conserved multi-functional protein essential for replication and translation of viral RNA and polyprotein processing. Early T-cell response against NS3 is capable of restricting viremia. We aimed at characterizing the immunogenicity in gene immunization of the conserved regions of NS3 critical for protein folding and activity. C57BL/6 mice were injected with NS3 gene of Russian HCV 1b isolate 274933RU. Immunization did not exert any overt histological changes and had no long-term effects on the immune status of NS3 gene-recipients. The immune response in NS3 gene-recipients was screened by antibody ELISA, T-cell proliferation test and immune assays for specific cytokine production. T-lymphocytes of NS3 gene-recipients proliferated in response to peptides representing conserved regions of protease and ATPase/helicase. Stimulated T-lymphocytes produced IL-2, and in response to protease-derived peptides, also IFN-γ. Potent and long-lasting antibody response was raised against conserved NS3 regions including “Greek-key” motif of protease, motifs II, V and polynucleotide-binding domains of ATPase/helicase. Thus, gene immunization effectively targeted conserved regions critical for NS3 protease and helicase function. In type and specificity, immune response of NS3 gene-immunized mice mimicked immunity achieved in the acute self-limiting HCV infection of human and primates and in virus-exposed healthy individuals, indicating promiscuity of NS3 as immunogen.