Immune response distinguishing self from non-self memoryImmunity: all mechanisms used by the body to protect itself against all things foreign microorganisms or their products foods, pollen, animal hair chemicals, drugsImmunity: innate or acquiredInnate immunity: all elements with which we are born, always present, available on short notice to protect; non-specific Body surfaces: skin, mucous membranes Chemical factors: secretions (sweat, sebum) Fever Phagocytes system with memory; specificHost defense mechanisms A. Outer barriers Skin and epithelial liningsSkin: keratinsweat (NaCl), sebum (unsat. fatty acids) Mucous membranes: mucus and ciliated epitheliumstomach - acidintestinal mucus - prevent attachment short-lived Monocytes large cells; long-lived, can divide leave bloodstream; enlarge to form macrophagesFixed macrophages: dust cells, Kuppfer cellsWandering macrophages: peritoneum, alveoliHost defense mechanisms B. Phagocytosis cells in blood phagosome3. Vesicle fuses with lysosome 4. Digestive enzymes destroy bacterial cell; peroxide bradykinin lowers neuron threshold; prostaglandin enhances the effectTemperature (localized): warm blood to surfaceenhances phagocytosis, inhibits bacteriaGradually: fibrin deposition to wall off areaaccumulation of dead cells -pusFever - generalized Prostaglandin from leukocytes Hypothalamus control centerEnhance phagocytosis Inhibit bacteriaAspirin!ACQUIRED IMMUNE RESPONSE Vaccination or immunization Active caseAntigen - foreign substance, usually protein or carbohydrate, cell componentAntibody - blood protein produced in response to a foreign substance; IMMUNOGLOBULINSystem with a memoryThe Lymphatic System stronger responseEPITOPEReactive portion; faceANTISERUMSerum with antibodies; antitoxinFate of an antigen1. Bloodstream to spleen2. Lodge in epidermal, dermal or subcutaneous tissue Inflammatory response Antigen (free; macrophages) to lymph nodes3. Gastrointestinal or Respiratory tract Macrophages cut to epitopes epitopes bond to MHC class II on surfaceT cell with appropriate receptor recognizes MHC + epitope(CD4 receptor on T cell) APC secretes Interleukin 1 (IL-1), activating T cell T cell secretes other IL moleculesIl-2 fungi, viruses tissue graft rejection cancer cellHarmful role: delayed hypersensitivity reactions: allergic contact dermatitis, infectious allergy (tuberculin)(contact dermatitis: molecule + skin protein carrier)Hypersensitivity ReactionsType I: anaphylaxis mediated by IgE rapid response: blood vessel dilation, hypotension, shock insect venomHypersensitivity ReactionsType I: anaphylaxis mediated by IgE rapid response: blood vessel dilation, hypotension, shock insect venomType II: cytolytic/cytotoxic reactions mediated by IgG, IgM bind to cell, initiate complement cascade phagocytes attack, releasing lytic enzymeshoursHypersensitivity ReactionsType I: anaphylaxis mediated by IgE rapid response: blood vessel dilation, hypotension, shock insect venomType II: cytolytic/cytotoxic reactions mediated by IgG, IgM bind to cell, initiate complement cascade phagocytes attack, releasing lytic enzymeshoursType IV: delayed hypersensitivity/cell mediated reactions mediated by T cells which release lymphokines macrophage accumulation and activation begins 18-24 hr, peak at 24-48 hr rash of small pox, measles; tuberculin reactionLymphokines macrophage chemotactic factor macrophage inhibiting factor macrophage activating factor (phagocytosis) mitogenic factor interferon interleukinsAUTOIMMUNITY mild to life-threatening disordersTolerance: immune system held in check a) antigen not exposed (inside cell, behind barrier) b) antigen not produced early c) B cells cut to epitopes epitopes bond to MHC class II on surfaceT cell with appropriate receptor recognizes MHC + epitope(CD4 receptor on T cell) APC secretes Interleukin 1 (IL-1), activating T cell T cell secretes other IL moleculesIl-2 & IL-4 activate T cell, causing proliferation & release or IL-4 & IL-5B cell proliferates into Plasma and Memory cells