PHAGOCYTES INNATE IMMUNITY (Invertebrates and vertebrates) COMPLEMENT AGGLUTININS 1. Must discriminate between self and non-self 2. Protection by neutralization or destruction of non-self structures Harvard-MIT Division of Health Sciences and TechnologyHST.176: Cellular and Molecular ImmunologyCourse Director: Dr. Shiv PillaiMultivalent foreign structure Receptors Internalization Signal transduction Crosslinked receptorsAGGLUTININS Neutralize Opsonize Fix Complement Discriminate between self and non-self Usually lectinsRepeated bacterial shape on surface Bivalent protein with binding sites for repeated shape on bacterial surface. A specific shape which can be recognized by the immune system may also be called an "epitope" or an "antigenic determinant"OPSONINS AND OPSONIZATION Microbe Opsonin Receptor Phagocyte PhagosomePattern Recognition ReceptorsSPECIFIC/ADAPTIVE IMMUNITY Generation of Diversity Self/non-self recognition MemoryAnticoagulated (non-clotted) blood Neutrophils Basophils Eosinophils Plasma Granulocytes Monocytes Lymphocytes White cells (leukocytes) Red cells (erythrocytes) Platelets (thrombocytes) Cells Coagulated (clotted) blood (Coagulum) Serum (Plasma minus clotting factors) ClotSpecific Immunity 1. Active versus Passive Immunity 2. Humoral versus Cell Mediated ImmunityY Agglutination Complement fixationY YYYCYY YYYYYY Neutralization Antibody dependent cellular cytotoxicity YYY Opsonization YYY"Immune receptor"/antibody foreign shapeantigen clonal expansion secretion of antibodiesY NO SIGNAL Y YY SIGNAL Y ENDOCYTOSED FOR ANTIGEN PRESENTATIONANTIGENS -II ALL IMMUNOGENS ARE ANTIGENS BUT ALL ANTIGENS ARE NOT IMMUNOGENSViral envelope protein MHC class I-peptide complex T T cell receptorINNATE IMMUNITY PHAGOCYTES (Invertebrates and vertebrates) COMPLEMENT AGGLUTININS (Vertebrates) SPECIFIC IMMUNITY MHC MOLECULES LYMPHOCYTES ANTIBODIESGeneration of Diversity Self-Nonself DiscriminationCentral lymphoid organs Periphery antigen receptor "The death window" Proliferation and activation Rearrangement Elimination of Final of immune self repertoire receptor genes reactive cells in respondersInitial lymphocyte repertoire is generated in central lymphoid organs the thymus) self antigen death self antigenself antigen deathdeath and (the bone marrow Immature cells die if stimulated After deletion of self reactive lymphocytes mature cells migrate to peripheral lymphoid organs foreign antigen E M M ME Mature cells proliferate and differentiate if stimulated Some activated cells exhibit memory (M) while others are revved up immune effectors (E) Effectors acquire the ability to leave lymph nodes and enter the tissues which contain the foreign antigen which they will zap or mop