The individual projects in the "Aging and Immunity to Infections" program require sophisticated molecular tools to analyze antigen-specific T and B cell responses, to characterize the expression of immune related genes, and to determine viral loads. The goal of the Molecular Biology Core is to support the individual projects by developing new molecular reagents and assays. In Aims 1 and 2 the Core will develop new MHC class I and class II staining reagents for the direct identification of antigen-specific CD8+ and CD4+ T cells. In Aim 3, the Core will develop new real-time PCR assays to quantitate mRNA expression for various viral and immune related genes, and for the quantification of viral genomes. And in Aim 4, the Core will develop approaches for the production and purification of proteins suitable for ELISAs. The Molecular Biology Core has extensive expertise in the development of these reagents and assays and preliminary data establish the feasibility of the approaches. Funds are only requested for the development of reagents and assays that are currently unavailable.