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MSU MMG 301 - Module 30

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Module 30Explain the general innate immunity mechanisms that protect against pathogens- Innate immunity (nonspecific immunity) involves mechanisms that work against all potential microbial pathogens; does not rely on previous exposure to a pathogen.- Innate Immunity is a preexisting ability to recognize pathogens or their toxins and destroy of inactivate them - innate immunity is carried out by cells now as phagocytes (specialized blood cells that engulf and kill most pathogens)- Carried out by cells known as phagocytes - antigen presenting cells (APCs), Eat the bacterial pathogens and then process them by degrading them using the phagosome intro its basic components, then release soluble debris and present pieces ofa pathogen on the cell surface-Self vs. non-self using receptors (pathogen recognition receptors - PRRs)Bacterial and viral pathogens have PAMPs that are recognized by the PRRs, alert an immune response that there are non-self molecules in the body.PAMPs - LPS (endotoxin), peptidoglycan, flagella - recognized by PRR which are found on phagocytes and allow them to bind pathogen and stimulate engulfment and degradationList the three main functions of adaptive immunity1. Recognize a pathogen and their toxins2. Discriminate between a pathogen and normal body cells3. Eliminate a pathogen and or toxin4. Also memoryDefine antigenAny molecule or portion of a molecule that stimulates a response in immune systemKnow how phagocytes recognize pathogens at the molecular level- Macrophages are usually the first line of defense against pathogens - Phagocytes recognize pathogen associated molecular patterns. This recognition occurs through pattern recognition receptors on the surface of phagocyte. The phagocytesbecome activated to ingest and destroy the pathogen, molecular pieces of the pathogen are then attached to protein complexes and presents on the call surface.Briefly describe how phagocytes destroy pathogensAfter contact with PAMP, phagocyte become activated to ingest and destroy the pathogen; Molecular pieces of the pathogen are then attached to protein complexes and presented on thecell surfaceDescribe the process of antigen presentation- Molecular pieces of the pathogen are then attached to protein complexes and presentedon the cell surface- Antigen on MHCII is recognized by TH1 cells, which release cytokines that induce inflammationAntigen on MHCI is recognized by TH2 cells, which stimulate antigen-reactive B cells to proliferate and produce antibodiesBe familiar with how T-cells are stimulated upon binding to antigen-presenting cell and the function of each T-cell type- Phagocytes ingest pathogens and present antigens on their surface. These are recognized by T cells. B cells also recognize antigens and produce antibodies.- T cells only recognize antigens on the surface of host cells that are presented on a protein complex, the major histocompatibility complex.Tc - cytotoxic cells: kill host cells that have been infected by a virus.Th- helper cells: Two types:- TH1 - release cytokines that induce inflammation- TH2 - stimulate antigen-reactive B cells to proliferate and produce antibodiesDefine super-antigen and describe how it works- Superantigens: bacterial exotoxins that interact indirectly with host T helper cells and antigen-presenting cells. Proteins produced by certain viral and bacterial pathogens. Bind outside the MHC T-cell receptor ending site. Result in activation of a large number of T-cells and production of cytokines, producing excessive inflammation and tissue damage.- Link TCR and MHC together, stimulating large immune response with activation of a large number of T cells with excessive inflammation and tissue damageBe able to label the major parts of an antibody moleculeKnow what part of an antibody binds to antigensThe variable part of the antibody binds to the antigen; the epitopeDefine epitopethe portion of an antigen that is recognized by an immunoglobulin or T cell receptor; also called antigenic determinantsKnow how natural immunity is acquiredAfter an infection, immunity to a pathogen developsBe able to describe what artificial immunity is, and discern active and passive artificial immunity- Artificial immunity: is a mean by which the body is given immunity to a disease by intentional exposure to small quantities of it- Active artificial immunity: uses vaccination to produce response that provides immunity;in some cases, additional subsequent booster vaccinations provide for longer immunity- Passive artificial immunity: no response of the immune system is involved - individual receives antibodies. Examples: injection of antiserum (serum containing antibodies against the specific pathogen or toxin) into a person recently infected or exposed to a toxin (i.e. snake anti-venom)Describe the 3 types of vaccines discussed- Toxoid: exotoxins that have been chemically inactivated but are still antigenic- Inactivated pathogen: pathogens (bacteria or viruses) are killed by reaction with a chemical compound or heat (Salk polio vaccine)- Live attenuated pathogen: a mutant variant of a pathogen is used; mutant cannot cause significant disease but will still stimulate immune system to produce immunityBe able to describe in very general terms how influenza vaccine is made- Seasonal influenza vaccines are made from viruses predicted to be prevalent in upcoming winter season.- First seed viruses from WHO/CDC and eggs from farms or human cell cultures, the propagation of virus in chick embryos or cell culture, then inactivation and purification. Each seasonal influenza vaccine usually contains three influenza viruses - one A virus, one regular seasonal A virus, and one B virus. Then tests for potency and sterility. Then packaging and


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