Adaptive Immunity (Specific Immunity) Why is this important?-Two lines of rapid defense against microbial pathogensoFirst line: skin and mucous membraneoSecond line: phagocytosis, interferons, complement, inflammation, and fever-All of these react non-specifically to an invading organism Don’t differentiate -In addition to these nonspecific defenses, our bodies respond specifically to individual microbes-Vaccination is an application of the specific immune response, stimulates your body to respond Overview of Adaptive Immunity-Adaptive immunity is the body's ability to recognize and defend itself against distinctinvaders (specific pathogens) and their products (toxins or chemicals they produce, etc.)-Five attributes of adaptive immunityoSpecificity-Particular immune response against only one particular molecular shapeand not against othersoInducibility-Cells of adaptive immunity are activated in response to specific pathogens -Has the potential to react to the Ebola virus, but has to be exposed to the Ebola virus before the active virus comes in contact with you-Ability to respond is there, but you have to be exposed first oClonality-Lymphocytes-One particular lymphocyte recognizes one specific piece of a pathogen and once this happens (these 2 bind) it stimulates the lymphocyte it causes the lymphocyte to undergo rounds of cell division (many cells recognize the pathogen) -Once induced, cells of adaptive immunity proliferate to form many generations of nearly identical cells -Clonal expansion: one cell forms a clone that recognizes the same thingsit did (B Cell) When they are stimulated they replicatedStart out with one cell and go through clonal expansion when the cell comes in contact with the virusoUnresponsiveness to self-Tell the difference from something belongs in your body and something that doesn’t -Organ transplant: match up proteins; always something that is different -antirejection drugsoMemory-Adapts to respond faster and more effectively -Involves activity of two main types of lymphocytes (WBC) that act against specific pathogens oB lymphocytes (B Cells): arise and mature in the red bone marrowoT lymphocytes (T Cells): arise in the red bone marrow and mature in the thymusoParticipate in 2 different branches of the immune response-Two types of adaptive immune responsesoB cells carry out antibody mediated immune responses-Humoral (fluid) immune response-Involved with antibodies-Act against extracellular pathogensIn our bodies, but not inside host cell-T cells help regulate and fulfill antibody immune responses oCell mediated immune responses are controlled and carried out by T cells-Often act against intracellular pathogensEffective against pathogens inside the body and inside the host cells -Both types stimulate and regulate innate immunity as well as act directly against the specific pathogen that initiated the adaptive response Elements of Adaptive Immunity (Actors in the play)-Lymphatic system: the organs, tissues, and cells of adaptive immunity oComponents constitute a surveillance system that screens the tissues of the body - particularly possible points of entry - for foreign molecules-Antigens: the molecules that trigger adaptive immune responses -Antibodies-Chemical signals and mediators The Tissues and Organs of the Lymphatic System-Components constitute a surveillance system that screens the tissues of the body - (particularly possible points of entry: mouth, nose, intestines) - for foreign molecules-Lymphatic vessels conduct the flow of lymph Lymphatic Vessels and the Flow of Lymph-Form a one-way system that conducts lymph from local tissues and returns it to the circulatory systemoFrom extremities back to the heart-As it does so it goes through lymph nodesoLymph arises from fluid leaked from blood vessels into surrounding tissuesoPicks up anything that it finds in the tissues and passes it through lymph nodes and produces an inflammatory response -Lymph carries toxins and pathogens to areas where lymphocytes are concentrated-First collected by lymphatic capillaries, passes into larger lymphatic vessels, and thenflows into lymphatic ducts-Lymph only flows toward the heart-Lymph nodes (~1000) house leukocytes (WBCs) that recognize and attach foreigners present in the lymph Lymphoid Organs-Primary lymphoid organs: red bone marrow and thymus-Secondary lymphoid organs and tissues: lymph nodes, spleen, tonsils, and MALT (mucosal associated lymphoid tissue)oLymph nodes filter lymph, while the spleen filters blood and removes bacteria, viruses, toxins, and other foreign matter from the blood-MALT includes the appendix; lymphoid tissue of the respiratory tract, vagina, urinarybladder, and mammary glands; and Peyer's patches in the small intestineoContains most of the body's lymphocytes Antigens-Generates antibody response-Body responds with one cell with each antigenic determinant (may recognize circles, squares, triangles, etc.)-Each lymphocyte recognizes a different antigenic determinants-Many pieces of a protein (antigens) that generate an immune response; need a different lymphocyte for each antigen-Adaptive immune responses are directed against portions of cells, viruses, and even parts of single molecules that the body recognizes as foreign and worthy of attackoThese biochemical shapes are known as antigens and they bind to lymphocytes and trigger adaptive immune responsesProperties of Antigens-Good antigen: what stimulates the best immune response?oProtein: very complex - can end up with many antigenic determinantsoPolysaccharide: may only have one antigenic determinant because it is a repeating unit-Properties that make certain molecules more effective at provoking adaptive immunity are a molecule's shape, size, and complexityoThe body recognizes antigens by the 3-D shapes of regions called epitopes (antigenic determinants)-Larger molecules are better antigens than smaller ones -Most effective are large foreign macromolecules such as proteins and glycoproteins-Complex molecules make better antigens because they have more epitopes-Examples: components of bacterial cell walls (NAG and NAM; peptidoglycan), capsules (sugar), pili, flagella (protein), viral proteins, fungal proteins, protozoal proteins, toxins, and some nucleic acid molecules Types of Antigens3 types of antigens -ExogenousoB cells are involvedoIn body, but not within host cell - in tissueoVirus can be considered exogenous-After the host cell lyses-Before the