ONE-STEP AHEAD OF THE GAME - VIRAL IMMUNOMODULATORY MOLECULES

For decades cell biologists have relied on viruses to facilitate the s tudy of complex cellular function. More recently, the tragedy of the A IDS epidemic has focused considerable human and financial resources on both virology and immunology, resulting in the generation of new info rmation relating these disciplines. As the miracle of the mammalian im mune system unfolds in the laboratory, the elegance of the mechanisms used by co-evolving viruses to circumvent detection and destruction by the host becomes inescapably obvious. Although many observations of v irus-induced phenomena that likely contribute to the virus's escape of immune surveillance are still empirical, many other such phenomena ha ve now been defined at the molecular level and confirmed in in vivo mo dels. Immune modulators encoded within viral genomes include proteins that regulate antigen presentation, function as cytokines or cytokine antagonists, inhibit apoptosis, and interrupt the complement cascade. The identification of such gene products and the elucidation of their function have substantially strengthened our understanding of specific virus-host interactions and, unexpectedly, have contributed to the re cognition of potent synergy between viruses, which can result in an un predictable exacerbation of disease in co-infected individuals. Becaus e many viral immune modulators clearly have host counterparts, viruses provide a valuable method for studying normal immune mechanisms. It i s conceivable that an improved understanding of virus-encoded immunomo dulators will enhance our ability to design reagents for use in therap eutic intervention in disease and in vaccine development.