The overall goal of this project is to develop a safe and effective multivalent M protein-base d vaccine to prevent acute rheumatic fever (ARF). Rheumatic fever is triggered by group A streptococcal infections of the throat. Although the incidence of ARF has declined markedly in the U.S. and other developed countries over the past 50 years, the disease remains rampant in developing countries of the world. Rheumatic heart disease (RHD) is the leading cause of heart disease in children throughout the world. An estimated 12 million people suffer from chronic RHD and 400,000 die from the disease each year. Thus, the development of an effective vaccine designed to prevent the streptococcal infections that cause ARF and RHD could significantly improve the health of millions of children around the world. The aims of this proposal are: 1) To determine the distribution of group A streptococcal serotypes causing acute pharyngitis in countries where ARF is common, 2) to determine the optimal formulation and route of delivery of multivalent group A streptococcal vaccines using an established mouse model, 3) to identify T cell epitopes within multivalent vaccines in order to enhance the overall protective antibody responses to the multivalent vaccines, 4) to translate these findings into the design, construction, GMP production, and formulation of a multivalent vaccine to prevent rheumatic fever, and 5) to perform a phase I clinical trial to assess the safety and immunogenicity of the vaccine in adult volunteers. Prospective studies will be conducted in Mall, West Africa and Leon, Nicaragua to identify the prevalent rheumatogenic serotypes. This information will be combined with available data on the emm-type distribution of clinical isolates from around the world. Laboratory studies in animals will establish the optimal formulation and route of delivery for the vaccine. The final vaccine will be produced and manufactured to GMP standards by ID Biomedical Corporation. The proposed phase I clinical trial will be performed at the University of Maryland and will establish the safety and immunogenicity of the vaccine in human adult volunteers. Successful completion of these studies will bring us one step closer to determining whether acute rheumatic fever is a vaccine preventable disease.