麻省理工学院 生物材料课程 lecture 8 Cell-Surface Interactions Host Responses to Biomaterials (Part II).pdfVIP

3.051J/20.340J 1 Lecture 8: Cell-Surface Interactions: Host Responses to Biomaterials (Part II) Implantation of a biomaterial initiates the inflammatory response: - response of vascularized tissue to local injury - severity indicates biocompatibility of material Cooperative Signaling Cascades: 1. Coagulation Cascade initiated by adsorbed 2. Complement Alternative Pathway proteins The complement is a component of the immune system. Immune system function: to protect against pathogens Innate (Native) Immunity Adaptive (Aquired) Immunity - first line of defense - specificity to distinct foreign biomolecules (antigens) - nonspecific response to invading pathogens - memory of exposure - elicits adaptive response Physical/chemical barriers: Blood proteins: epithelia, antimicrobial proteins antibodies (immunoglobulins), cytokines Blood proteins: complement; cytokines (regulatory) Cells: lymphocytes (T cells, B cells) Cells: phagocytes (macrophages, neutrophils), natural killer cells 3.051J/20.340J 2 Complement - system of 30 proteins that mediate immune response - discriminates “foreign” from “self” through adsorbed proteins/ protein fragments (C3b, C4b) - recruit and activate phagocytes (C3a, C5a) - lysis of pathogens via membrane pore formation (C5b, C6-C9) 3 recognized pathways (to C5 convertase) Classical pathway: antigen-antibody immune comp