Retraction

IMMUNOLOGY. For the article “Prophylactic DNA vaccine for hepatitis C virus (HCV) infection: HCV-specific cytotoxic T lymphocyte induction and protection from HCV-recombinant vaccinia infection in an HLA-A2.1 transgenic mouse model” by Tatsumi Arichi, Takafumi Saito, Marian E. Major, Igor M. Belyakov, Mutsunori Shirai, Victor H. Engelhard, Stephen M. Feinstone, and Jay A. Berzofsky, which appeared in number 1, January 4, 2000, of Proc. Natl. Acad. Sci. USA (97, 297–302), the undersigned authors note the following: “We deeply regret to report that we have discovered that the virus protection data in Figs. 4–6 of our PNAS paper have been fabricated and the paper must be retracted. We have not been able to reproduce the growth in vivo in mice of the NYVAC-based challenge recombinant vaccinia virus expressing the HCV core protein. We later learned that the NYVAC strain of vaccinia used in this particular study is attenuated in mice, in contrast to the WR strain-based vaccinia recombinants widely used elsewhere by us and others, that do grow well in mice. Dr. Arichi, the first author, has now admitted in writing that he spiked some of the ovary homogenates reported in Figs. 4, 5, and 6 with calculated quantities of stock virus, resulting in the titers reported in the paper. These actions were taken without the knowledge of the other authors. We deeply regret that this serious problem occurred, and we sincerely apologize to any of our colleagues who have been misled or inconvenienced by this publication.”