INDUCTION OF HUMAN-IMMUNODEFICIENCY-VIRUS TYPE-1 (HIV-1)-SPECIFIC CYTOLYTIC T-LYMPHOCYTE RESPONSES IN SERONEGATIVE ADULTS BY A NONREPLICATING, HOST-RANGE-RESTRICTED CANARYPOX VECTOR (ALVAC) CARRYING THE HIV-1(MN) ENV GENE

CD8(+) cytolytic T lymphocytes (CTL) are likely to be an important com ponent of effective vaccines against human immunodeficiency virus type 1 (HIV-1). CTL can be induced most effectively with live virus vector s, However, because of concerns about the safety of such vectors, a no nreplicating canarypox vector (ALVAC) capable of expressing foreign ge nes in mammalian dells has been developed, This study evaluated the ca pacity of an ALVAC vector expressing the HIV-1(MN) envelope (env) glyc oprotein to induce HIV-1-specific CTL in seronegative volunteers, Prot ocols were designed to determine whether immunization with ALVAC alone or in combination with subunit boosting could induce CTL in vaccinia- immune and -naive volunteers, A simple method for antigen-specific in vitro stimulation was used to detect CTL responses in HIV-1-seronegati ve vaccine recipients, The results indicate that low doses of a nonrep licating virus vector alone can elicit both CD4(+) and CD8(+) HIV-1-sp ecific CTL in a subset of seronegative volunteers.