Protection against woodchuck hepatitis virus (WHV) infection by gene gun coimmunization with WHV core and interleukin-12
García-Navarro R, Blanco-Urgoiti B, Berraondo P, Sánchez de la Rosa R, Vales A, Hervás-Stubbs S, Lasarte JJ, Borrás F, Ruiz J, Prieto J.
Division of Hepatology and Gene Therapy, University Clinic and Medical School, University of Navarra, Pamplona, Spain.
Woodchuck hepatitis virus (WHV) and hepatitis B virus (HBV) are closely similar with respect to genomic organization, host antiviral responses, and pathobiology of the infection.
T-cell immunity against viral nucleocapsid (HBcAg or WHcAg) has been shown to play a critical role in viral clearance and protection against infection. Here we show that vaccination of healthy woodchucks by gene gun bombardment with a plasmid coding for WHcAg (pCw) stimulates proliferation of WHcAg-specific T cells but that these cells do not produce significant levels of gamma interferon (IFN-gamma) upon antigen stimulation. In addition, animals vaccinated with pCw alone were not protected against WHV inoculation. In order to induce a Th1 cytokine response, another group of woodchucks was immunized with pCw together with another plasmid coding for woodchuck interleukin-12 (IL-12).
These animals exhibited WHcAg-specific T-cell proliferation with high IFN-gamma production and were protected against challenge with WHV, showing no viremia or low-level transient viremia after WHV inoculation. In conclusion, gene gun immunization with WHV core generates a non-Th1 type of response which does not protect against experimental infection. However, steering the immune response to a Th1 cytokine profile by IL-12 coadministration achieves protective immunity.
These data demonstrate a crucial role of Th1 responses in the control of hepadnavirus replication and suggest new approaches to inducing protection against HBV infection.
CITA DEL ARTÍCULO J Virol. 2001 Oct;75(19):9068-76