Functional and structural characteristics of bacterial proteins that bind host cytokines

Several human pathogens bind and respond to host cytokines, which can be considered a virulence mechanism that communicates defensive actions of the host to the pathogen. This review summarizes the current knowledge of bacterial cytokine-binding proteins, with a particular focus on their functional and structural characteristics. Many bacterial cytokine-binding proteins function in the development of infection and inflammation and mediate adhesion to host cells, suggesting multiple roles in pathogen-host interactions. The regions of the bacterial proteins that interact with host cytokines can display structural similarities to other proteins involved in cytokine signaling. However, there appears to be no central shared structural themes for bacterial cytokine-binding proteins, and they appear to possess structures that are different from the cytokine receptors of the host. Atomic-level information regarding receptor-cytokine interactions is needed to be able to disrupt these interactions and to elucidate the specific consequences of cytokine binding in a pathogen and host.