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What is immunolgy
Testing
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Primary purpose of immune system
Defense, Fluid Balance, Fat absorbtion
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Define Lymphatic tissue
- Conn tissue w/ matrix of lymphocytes
- Simple-diffuse lymphatic tissue
- No clear boundry
- Lymphatic nodules-densely packed lymphocytes in loose conn tissue
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Continued:
- Lymph nodules:
- spherical in shape-no capsule
- germinal centers-mitosis
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Lymphatic tissue found:
- beneathe epithelium of:
- respiratory tract
- digestive tract-Peyers patch
- urinary tract
- tonsils-pharyngeal (adenoid), palatine (tonsils), lingual
- appendix-fused nodules
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Lymph fluid:
Leaves capillaeries-does not reenter venous end-so enters lymphatic vessels-carries foreign antigens
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Lymph moved by
- Contraction of lymphatic vessesl(smooth muscle)
- skeletal muscle (muscle pump)
- thoracic pressure changes (respiratory pump)
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Thymus
- T cells migrate here from bone marrow
- bilobular-triange-superior to heart
- max size in puberty
- cortex (outer)T cells undergo mitosis
- medulla(inner)-self reactive T-cells deleted
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Nonspecific/Innate Immunity
Defense against all pathogens-no specifity
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1-physical barrier:
- Skin-Dry for microbes-acidic PH
- secrete sweat and sebaceous glands contain antimicrobila factor
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Tears-Saliva-contain Lysozyme-attack bacterial cell wall
Urine-Acidic-flush tract
Bile-inhibitory
Stomach-acidic PH-hostile
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2-Phagocytes-eat microbes-recognize-Pamps(pathogenic antigens)
- Lysozyme and acidic hydrolase carry out indigestion
- Hydrogen Peroxide(H2o2), Niric Oxide(NO2), superoxide anions(o-)-lethal to bacteria
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Types of Phagocytes:
- Fixed macrophages-alveolar macrophages-lives in lungs
- Free Macrophages-Mobile
- Neutrophils-in blood-eat bacteria
- Eosinophils-eat antigen-body complex
- Monocytes-In blood-leave blooda nd become macrophages
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Other phagocyte info:
Release chemotactic factors-call other phagocytes
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Opsonins:
- Molecules which increase phagocytosis
- EX-compliment proteins and antibodies
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3-Cellular Killing-Natural Killers:
- NK cells kill ALL tumors or virally infected cells
- have lrg granules in cytoplasm w/ perforin in them
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4-Inflammatory Response:
have toll like receptors
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Chemical factors involved in inflammation:
- 1-Histamine-released by basophils and mast cells
- causes vasoldilation in local region-makes leaky
- brings more blood
- plasma and wbc leave vessels migrate to tissue
- allows wall off-prevent spread of infection
- stimulates gland secretions-arrtacts eosinophils
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2-Leukotrienes
- produced by basophils and mast cells
- cause prolonged muscle contarction-in lungs,
- most potent stimulator of bronchiloe constriction
- increase vascular permeability-attract neutrophils and eosinophils
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3-prostaglandins
- made by all cells
- causes vasoldilation-increase permeability
- stimulate pain receptor
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4-Kinins:
- Polypeptides derived from plasma proteins
- causes vasodilation, increased permaebility
- stimulate pain
- attract netrophil
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5-Fever
- a pyrogen made of macrophages, bacterial cell components, and viruses
- inhinits pathoge replication
- peps up immune system
- causes macrophages to keep FE stored-inhibits bacteria
- 104 degrees can cause brain damage
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6-Interferons: chemicals released by Virally infected cells
- Act to inhibit viral replication
- act only on local neigh cells
- neigh cells crank metabolism to inhibit vral replication
- alpha, beta, gamma
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7-Complement system:
- 20 proteins found in blood
- exist in inactive form
- 3 major actions:
- cell wall of pathogen destroyed
- phagocytes attracted-act as opsinins
- inflammatory reponse
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Specific Immunity: Defense tailor made for each pathogen
does not see intact bacterium only antigens on the bacteria
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Lymphocytes-Specific Immunity
- T cells leave bone marrow-go to Thymus
- B cells don't go to thymus-go into circultation
- B cells mature in bone marrow
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Antigen: a molecule that elicits immune response
- Large-EX-proteins
- bad EX-Carbs
- only 6-8 amino acids what seen(antigenis determinant)-epitope
- a bacteria may have several diff antigens on surface
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Characteristics of Specific Immunity:
- 1-Specific
- 2-Exhibits memory
- 3-Diversity-a immune response to more that 1 mill antigens
- 4-Self vs. Nonself
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2 arms of spec immunity
- 1-Cellular Immunity-T cells are effectors
- 2-Humoral Immunity-Antibodies are effectors(B cells)
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Cytokines
- Very imp in immune system
- Direct activity of immune system
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Interleukins -chemical mess released between white blood cells
- 11-1-released by antigen presenting cells-stimulates T cell-acts on hypothalumus-brings fever
- 11-2-released by Th cells stimulate Tc cell then B cell
- Interferons are type of cytokine
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3 cell types in Specific Immunity:
- APC cells-Antigen presenting cells-B cell, dendritic cell, macrophage
- T cell-CD4(helper), CD8(killer)
- B cell-goes into plasma membrane secretes antobodies-stimulates CD4
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Macrophages/Dendritic cells-recognize and present pathogens
- have PAMP-pathogen ass mol pattern on their surface
- toll like receptors
- antigen process-eat antigens-chop into pieces
- then put on their surface with MHC-present antigen to T cell
- B cells also capable of presenting antigens to T cells
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Costimulation:
T cells need 2nd signal-the APC releases interleukin 1 to T cell to activate it
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Macrophage
also player in nonspecific immunity-will gobble up bacteria here too
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MHC: Major Histocompatibilty Complex-antigen/ marker on cells
2 classes:
- MHC1-identify self cells-on all nucleated cells-transplant rejection if antigens of donor and reciever not matched
- MHCII-only on antigen presenting cells
- MUST presnt antigen to T cell or T cell won't recognize antigen
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T cells 3 subsets:
- Th-CD4 helper cell-conduct immune respose
- nothing happens if not directed by Th cells
- Tb-CD8-cytotoxic T cells-killers
- B cells-make antibodies when activated by Th cells-CAn do without Th cells sometimes
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CD 8 cells:
- also release granzymes on top of perforin-granzymes enter target cell and cause fragmentation of target cell DNA (apoptosis-cell suicide)
- clones are made
- memory cells made
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Tregs:
Active in supressing immune system
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B cells:
- cells are cloned
- make antibody specific for antigen
- can pump 2000 antibodies
- BUT only 1 specific antibody
- memory cells also made
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Specific Immune Response:
Take place in immune organs-lymph nodse, spleen
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Recap:
- 11-1-secreted by macrophages stimulates T cells
- 11-2-made by CD4/Th cells and stimulates immune system
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Who must see the antigen?
ALL of the immune cell players
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Antibodies made of?
- Immunoglobulins
- overall shape of a Y
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Antibodise made of 4 chains:
- 2 heavy chains-identical, constan region, variable region-variable region binds to antigen
- 2 light chains-indentical, constant portion,variable portion, variable portion binds to antigen
- Antibody has binding site for complement and binding site for macrophages,basophils and mast cells
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5 classes of antibodies:
MADEG
- IgM-in blood, 1st antibody in immune response,large, 5 antibodies linked tog,initiates complement system
- IgA-in blood and mom's milk secretions, 2 antobody linked tog, makes mucosal immunity-released in gut and vagina
- IgD-in B cell, serves as B cell receptor
- IgE-in blood-active in allergy and inflammtion
- IgG-in blood, large quantities in memory resones, small can cross placenta
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Antibodies:
- may bind to viruses and prevent from attach to self cell
- bind to toxin and render harmlesss(neutralization by antitoxins)
- may bind to surface of antigen and glue pathogens tog(agglutination)-disables pathogens
- may bind to pathogesn and disbale them(clump recipitates out of the solution)
- may bind to antigen and enhance phagocytosis(opsinization)
- may stimulate inflammation
- may initiate compliment system
- ARE the most effective against EXTRACELLULAR PATHOGENS!!!!
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Cellular Immunity carried out by CD8/Tc cells- kills self altered cells
- must have antigen presented by altered slef cell w/MHC1 mol
- must have command of CD4/Th cell
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Tolerance:
- State of nonresponsiveness of immune system to specific antigen-results overexposure to that antigen
- prevents immune rseponse to self antigens
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Tolerance induced by:
- Deletion-of self reactive lymphocytse in thymus prenatally
- Preventing either signal that activates lymphocyes
- Suppression of T reg cells
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Immunity classified by how aquired:
- Genetic-specise specified
- Avtive-you make the immune respones:
- natural active-acquired through normal exposure
- artificial active-vaccination
- Passive Immunity-you dont make immune response
- natural passive-antibodies passed from mom to baby
- artificial passive-recieve immune cells from shot of someone elses antibodise-gamma globulin shot
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