We recently developed a novel vaccine based on the ectodomain of the RSV small hydrophobic protein. The aim of this project is to elucidate the mechanism by which SHe based vaccination protects against RSV infections. As SHe specific immune serum or monoclonal antibodies do not neutralize RSV infection in vitro, we will investigate the role of immune cells in vaccination induced immunity in vivo. More specifically we will investigate the potential involvement of T cell immunity and antibody dependent killing of infected cells by Macrophages or NK cells.