Our research lies at the intersection between vaccinology and structural biology. We use X-ray crystallography and other biochemical and biophysical approaches to aid in developing vaccines against the mucosal bacterial pathogens meningococcus and gonococcus. Meningococci cause potentially fatal cases of sepsis and meningitis and gonococcus causes sexually-transmitted infections, which are increasingly resistant to antibiotics. Our vaccine approaches against these pathogens include mutant Factor H binding protein (FHbp) and Neisserial surface protein A (NspA) antigens designed to disrupt the interaction with human complement Factor H, as well as outer membrane vesicles that have increased abundance of the mutant antigens. We are also collaborating on a gonococcal vaccine based on a peptide that mimics a sugar on the surface of the bacteria. From the structures of antibodies bound to vaccine antigens, we gain information both to develop improved antigens and to understand the human antibody repertoire induced by vaccination.