
<ArticleTitle>Vaccination with a Shigella DNA vaccine vector induces antigen-specific CD8(+) T cells and antiviral protective immunity.</ArticleTitle>
<AbstractText>A prototype Shigella human immunodeficiency virus type 1 (HIV-1) <prot>gp120</prot> DNA vaccine vector was constructed and evaluated for immunogenicity in a murine model. For comparative purposes, mice were also vaccinated with a vaccinia virus-env (vaccinia-env) vector or the <prot>gp120</prot> DNA vaccine alone. Enumeration of the CD8(+)-T-cell responses to <prot>gp120</prot> after vaccination using a <prot><prot>gamma interferon</prot> enzyme</prot>-linked spot assay revealed that a single intranasal dose of the Shigella HIV-1 <prot>gp120</prot> DNA vaccine vector elicited a CD8(+) T-cell response to <prot>gp120</prot>, the magnitude of which was comparable to the sizes of the analogous responses to <prot>gp120</prot> that developed in mice vaccinated intraperitoneally with the vaccinia-env vector or intramuscularly with the <prot>gp120</prot> DNA vaccine. In addition, a single dose of the Shigella <prot>gp120</prot> DNA vaccine vector afforded significant protection against a vaccinia-env challenge. Moreover, the number of vaccinia-env PFU recovered in mice vaccinated intranasally with the Shigella vector was about fivefold less than the number recovered from mice vaccinated intramuscularly with the <prot>gp120</prot> DNA vaccine. Since the Shigella vector did not express detectable levels of <prot>gp120</prot>, this report confirms that Shigella vectors are capable of delivering passenger DNA vaccines to host cells and inducing robust CD8(+) T-cell responses to antigens expressed by the DNA vaccines. Furthermore, to our knowledge, this is the first documentation of antiviral protective immunity following vaccination with a live Shigella DNA vaccine vector.</AbstractText>
