EpIgG is an interdisciplinary research constellation that is addressing a central question within infection medicine: Which antibodies are protective against a given pathogen and which may lead to a destructive host response? Immunoglobulin G (IgG) antibodies are crucial for the defense against pathogenic bacteria, underlined by the fact that most bacterial pathogens have developed strategies to counteract IgG that bind to their surface. Improved ability of distinguishing IgG with protective properties from IgG associated with a pathologic immune response may have important implications for the prevention and treatment of infectious diseases. To reach these research goals EpIgG brings together five research groups associated with several state-of-the art technologies. Long-term implications of the achieved results may support the development of new therapeutics or vaccines, which is of highest importance as antibiotics resistant bacteria represents a major threat against human health.