In vivo priming of virus-specific cytotoxic T lymphocytes with synthetic lipopeptide vaccine

CYTOTOXIC T lymphocytes (CTL) constitute an essential part of the immune response against viral infections 1 . Such CTL recognize peptides derived from viral proteins together with major histocompatibility complex (MHC) class I molecules on the surface of infected cells 2–4 , and usually require in vivo priming with infectious virus 5 . Here we report that synthetic viral peptides covalently linked to tripalmitoyl- S -glycerylcysteinyl-seryl-serine (P 3 CSS) can efficiently prime influenza-virus-specific CTL in vivo . These lipopeptides are able to induce the same high-affinity CTL as does the infectious virus. Our data are not only relevant to vaccine development, but also have a bearing on basic immune processes leading to the transition of virgin T cells to activated effector cells in vivo , and to antigen presentation by MHC class I molecules.