ABSTRACT
A key requirement for the success of biomaterial implants is to achieve an adapted interaction with the immune system. Indeed, excessive immune cell activation will result in tissue damage and harmful consequences such as implant loosening. However, inhibition of immune cell function may favor infection and finally force implant removal. It is well accepted that so-called professional phagocytes,
including granulocytes and mononuclear phagocytes, play a major role in interacting with foreign materials. Indeed, these cells may act as effectors of tissue or pathogen destruction, and influence the development of adaptive immune responses either through antigen presentation to T-lymphocytes or through cross-talk with lymphocytes through soluble substances or contact interaction. Importantly, phagocyte interaction with foreign materials may lead to widely varying outcomes. Understanding the basic mechanisms of phagocyte decision-making at interfaces is, therefore, of considerable practical importance. In addition, a current challenge for cell biologists is to understand how cells integrate environmental signals to chose a particular fate concerning important processes such as survival, proliferation, differentiation, migration or secretion. The purpose of the present review is to describe recent advances strongly supporting the view that physical cues play an important role in phagocyte decisions at interfaces. We shall briefly review basic data on phagocyte function and biochemical control. Then we shall describe recently published results concerning cell response to physical messages, with an emphasis on professional phagocytes. Finally, we shall review potential mechanisms for signal generation at the cell-material interface in order to suggest possible explanations for phagocyte behavior at interfaces.
