Induction of mucosal homing virus-specific CD8(+) T lymphocytes by attenuated simian immunodeficiency virus

Induction of virus-specific T-cell responses in mucosal as well as systemic compartments of the immune system is likely to be a critical feature of an effective AIDS vaccine. We investigated whether virus-specific CD8(+) lymp hocytes induced in rhesus macaques by immunization with attenuated simian i mmunodeficiency virus (SIV), an approach that is highly effective in elicit ing protection against mucosal challenge, express the mucosa-homing recepto r alpha 4 beta 7 and traffic to the intestinal mucosa. SIV-specific CD8(+) T cells expressing alpha 4 beta 7 were detected in peripheral blood and int estine of macaques infected with attenuated SIV. In contrast, virus-specifi c T cells in blood of animals immunized cutaneously by a combined DNA-modif ied vaccinia virus Ankara regimen did not express alpha 4 beta 7. These res ults demonstrate the selective induction of SIV-specific CD8+ T lymphocytes expressing alpha 4 beta 7 by a vaccine approach that replicates in mucosal tissue and suggest that induction of virus-specific lymphocytes that are a ble to home to mucosal sites may be an important characteristic of a succes sful AIDS vaccine.