Lecture: Week 12 Immunization and Immune Disorders PDF

Week 12 Immunization and Immune Disorders Chapters 17 and 18 Outline History of Immunization Active vs Passive Immunization Immune Testing Hypersensitivities Autoimmune diseases Immunodeficiency diseases (primary vs acquired) Brief History of Immunization 1796 – Edward Jenner disco...

Week 12 Immunization and Immune Disorders Chapters 17 and 18 Outline History of Immunization Active vs Passive Immunization Immune Testing Hypersensitivities Autoimmune diseases Immunodeficiency diseases (primary vs acquired) Brief History of Immunization 1796 – Edward Jenner discovered process of vaccination 1879 – Louis Pasteur developed a vaccine against Pasteurella multocida Antibody transfer developed when it was discovered vaccines  Brief History of Immunization 1796 – Edward Jenner discovered process of vaccination 1879 – Louis Pasteur developed a vaccine against Pasteurella multocida Antibody transfer developed when it was discovered vaccines While vaccines have a very good track record there are still challenges in the field. Many developing nations do not receive vaccines Effective vaccines not developed for some pathogens Vaccine-associated risks discourage investment in developing new vaccines Anti vaccine movement spreads false information regarding safety of vaccines. Types of Immunity Acquired During One’s life. Naturally acquired Artificially acquired Distinguished as either active or passive Active – bodies own immune response, catching a cold, immunizations Passive -- Receive antibodies from  There are different types of Active Immunization (vaccines) Attenuated (live) Inactivated (killed) vaccines vaccines Whole-agent vaccines Use pathogens with reduced Subunit vaccines virulence Both safer than live Can result in mild infections vaccines Active microbes stimulate a Microbes don’t provide many antigenic molecules to strong immune response stimulate the immune Can provide contact immunity response Modified microbes may retain Often contain adjuvants Chemicals added to enough residual virulence to increase effective cause disease antigenicity Toxoid vaccines – use an inactive toxin as an antigen as opposed to an organism. Chemically or thermally modified toxins used to stimulate immunity Useful for some bacterial diseases Stimulate antibody-mediated immunity Require multiple doses because they possess few antigenic determinants diphtheria, tetanus, and whooping cough (pertu ombination vaccines Administration of antigens from several pathogens Vaccines using recombinant gene technology attempts to make vaccines more effective, cheaper, safer. Variety of techniques used to improve vaccines Vaccines using recombinant gene technology attempts to make vaccines more effective, cheaper, safer.  Vaccine manufacture is generally done by growing microbes in culture vessels. Viruses are cultured inside chicken eggs. Individuals with egg allergies must avoid some vaccines  Vaccines are not perfect but they are far better than the alternative. Problems associated with immunization Mild toxicity most common Risk of anaphylactic shock Residual virulence from attenuated viruses Allegations that certain vaccines cause autism, diabetes, and asthma **Research has not substantiated these allegations  Mouse is injected Long-lived myeloma cell with antigen. lines are grown in culture. Passive Immunotherapy is the administration of antiserum Plasma cells, which secrete containing preformed antibodies antibodies, are removed. Antibodies Immediate protection against recent infection or ongoing disease Hybridomas are formed by mixing and fusing Hybridoma Antisera have several limitations plasma cells and myeloma cells; they are long lived and produce antibodies. Contain antibodies against many antigens Hybridomas are Can trigger allergic reactions called placed individually in small wells, and serum sickness their antibodies are tested for reactivity Viral pathogens may contaminate against the antigen. antisera Antibodies of antisera are degraded A hybridoma that makes antibodies that react relatively quickly with the antigen is cloned. Monoclonal antibodies Limitations are overcome through Hybridoma clone development of hybridomas  Antibody (IgG, IgM) concentration (titer) Passive immunotherapy How does your Injection immune system react differently to the different Active Boosters types of therapy? immunizatio Initial inoculation Time Group Questions 1) If you want to have immunity for a long time should you use passive or active immune therapy? Why do these therapies last different lengths of time? 2) You have identified a virus that is causing a disease. Describe how you would develop a vaccine (immuno therapy) to defend against this virus.  Take home messages: Vaccines while not without risk are extremely potent tools to fight infectious disease. Active immunotherapy includes vaccines which can come in the form of live organisms, dead organisms, purified proteins, or multiple proteins. Passive therapy is the acquisition of antibodies from some other means, direct injection. Outline History of Immunization Active vs Passive Immunization Immune Testing Hypersensitivities Autoimmune diseases Immunodeficiency diseases (primary vs acquired)  Serological tests use antigens and corresponding antibodies. Uses serology Study and diagnostic use of antigenantibody interactions in blood serum Two categories of immune testing Direct testing Indirect testing Test is chosen based on the suspected diagnosis, cost, and speed with which a result can be obtained.  Precipitation tests are one of the easiest serological tests. Antigens and antibody mixed in the proper proportion form large complexes called precipitates Immunodiffusion Determines optimal antibody and antigen concentrations  Immunodiffusion determines optimal antibody and antigen concentrations.  Agglutination tests involve the clumping of insoluble particles not the aggregation of soluble molecules. Cross-linking of antibodies with particulate antigens causes agglutination Agglutination is the clumping of insoluble particles Precipitation involves the aggregation of soluble molecules Reactions are easy to see and interpret with the unaided eye Hemagglutination Agglutination of red blood cells  Viral Neutralization Test Cytopathic effect is when viruses will kill appropriate cell cultures. Virus is first mixed with antibodies against it Ability of virus to kill culture cells is neutralized Absence of cytopathic effect indicates presence of antibodies. Tests identify whether individual has been exposed to a particular virus or viral strain.  Labeled Antibody Tests use antibody molecules linked to some “label” that enables them to be easily detected. Used to detect either antigens or antibodies Variety of different ways this can be done. Radioactivity and fluorescent dyes are two of the more common readouts. Fluorescein is one dye used in these tests Fluorescein-labeled antibodies used in two types of tests Direct fluorescent antibody tests Indirect fluorescent antibody tests Direct Fluorescent Antibody Tests: Looks for a specific antigen in a tissue. Flood the tissue with antibody that bound to a fluorescent marker that will specifically bind to the antigen you think is there. Indirect Fluorescent Antibody Tests ELISA: Enzyme linked immunosorbent assay Enzyme-linked immunosorbent assay Uses an enzyme as the label Reaction of enzyme with its substrate produces colored product Commonly used to detect presence of antibodies in serum  Antibody sandwich ELISA Modification of the ELISA technique Commonly used to detect antigen Antigen being tested for is “sandwiched” between two antibody molecules  Advantages of the ELISA Can detect either antibody or antigen – detection of antibody is an indirect test -- detection of antigen is a direct test Can quantify amounts of antigen or antibody Easy to perform and can test many samples quickly Plates coated with antigen and gelatin can be stored for later testing  Western blot test or the western blot Technique to detect antibodies against multiple antigens Advantages over other tests Can detect many types of proteins, each well could have many different types of proteins and we can repeatedly use many different antibodies to test for them. Less subject to misinterpretation  Western blot test or the western blot Technique to detect antibodies against multiple antigens Advantages over other tests Can detect many types of proteins, each well could have many different types of proteins and we can repeatedly use many different antibodies to test for them. Less subject to misinterpretation  Immunoblot or the Western blot Technique to detect antibodies against multiple antigens Advantages over other tests Can detect many types of proteins, each well could have many different types of proteins and we can repeatedly use many different antibodies to test for them. Less subject to misinterpretation  Ideally when performing an immune assay you want an answer right away. Immunofiltration – Like an ELISA but antibodies bind to a membrane and this makes it much quicker. Immunochromatography -- Very rapid and easy-to-read ELISAs Antigen solution flows through a porous strip and encounters labeled antibody Visible line produced when antigen-antibody immune complexes encounter antibody against them Used for pregnancy testing and rapid identification of infectious agents Figure 17.16 Immunochromatographic dipstick Zone of antibodies linked to colloidal metal, color too diffuse to see Line of fixed anti-antibody Used for pregnancy testing and rapid Strep Dip A identification of Strep A infectious agents such as streptococcus. Anti-antibodies stop movement of antibody- antigen complexes. Color becomes visible because of density of complexes. Dip Movement of fluid containing complexes of Prepared antigen antibodies extract from patient’s bound to nasal sample antigen Take home messages: We can use immune testing in a wide variety of ways in both the clinic and the lab. Direct testing looks for the present of antigens. Indirect testing looks for the present of antibodies. All of these tests need a readout and one of the best readouts is fluorescence. Outline History of Immunization Active vs Passive Immunization Immune Testing Hypersensitivities Autoimmune diseases Immunodeficiency diseases (primary vs acquired) Chapter 18 Immune Disorders: Hypersensitivity: Any immune response against a foreign antigen exaggerated beyond what is considered normal Four types Type I (immediate) Type II (cytotoxic) Type III (immune complex–mediated) Type IV (delayed or cell-mediated)  Type I (Immediate) Allergen (antigen) Hypersensitivity commonly Antigen-presenting cell (APC) phagocytizes and processes what we think of as allergies. antigen. Results from the release of APC presents epitope to Th2 cell. inflammatory Th2 cell molecules in IL-4 IL-4 from Th2 cell stimulates selected B cell B cell clone. response to an B cells become plasma cells antigen Plasma that secrete IgE. Localized or systemic cell IgE against allergen reaction IgE stem binds to mast cells, basophils, and eosinophils. Develop soon after exposure to an antigen IgE Basophil Eosinophil Mast cell Sensitization  Roles of degranulating cells in an allergic reaction Degranulation occurs after cells are sensitized. Mast cells – secrete kinins and Sensitized mast cell, proteases basophil, or eosinophi Basophils – similar to mast Subsequent exp cells to allergen Eosinophils – secrete Histamines, kinins, leukotrienes proteases, leukotrienes, prostaglandins, and other inflammatory molecules Degranulation  Clinical signs of localized allergic reactions are usually mild but can be severe. Usually mild Diagnosis of allergen Site of reaction depends on portal of entry Small inhaled allergens may reach lungs and cause asthma Some foods contain allergens May cause diarrhea and other gastrointestinal signs and symptoms Local skin inflammation may produce hives or urticarial (hives)  Prevention of Treatment of type I type I hypersensitivity hypersensitivity Identify and avoid allergens Administer drugs that Identify food allergens by counteract inflammatory eliminating suspected foods mediators from diet Antihistamines neutralize Immunotherapy can help histamine prevent allergic reactions Treat asthma with a Administer a series of corticosteroid and a injections of dilute allergen bronchodilator Must be repeated every two to three years Epinephrine neutralizes many mechanisms of anaphylaxis Relaxes smooth muscle  Type II (Cytotoxic) Hypersensitivity Results when cells are destroyed by an immune response Often the combined activities of complement and antibodies A component of many autoimmune diseases Two significant examples Destruction of blood cells following an incompatible blood transfusion Destruction of fetal red blood cells in hemolytic disease of the newborn  Red Blood Cell A, B, and O types Blood type O Blood type A Think of red blood cells as A donuts and the blood A A A types are the sprinkles. A A A Some people have donuts that have A sprinkles Blood type A B Blood type B some have B sprinkles some have both and some BA B B B B A B B have none. A B B B A BA BB B Our immune system knows what proteins are on all of our cells and the immune system looks for proteins that do not look like self. Our immune system knows what proteins are on all of our cells and the immune system looks for proteins that do not look like self. Our immune system knows what proteins are on all of our cells and the immune system looks for proteins that do not look like self. Our immune system knows what proteins are on all of our cells and the immune system looks for proteins that do not look like self. Our immune system knows what proteins are on all of our cells and the immune system looks for proteins that do not look like self. Our immune system knows what proteins are on all of our cells and the immune system looks for proteins that do not look like self. Our immune system knows what proteins are on all of our cells and the immune system looks for proteins that do not look like self. Our immune system knows what proteins are on all of our cells and the immune system looks for proteins that do not look like self. Our immune system knows what proteins are on all of our cells and the immune system looks for proteins that do not look like self. Aside from O what would be another potential blood type donor? If a patient is given blood with an A or B antigen on it they must have that same antigen on their blood cells type. Type A antigens on red blood cells of patient Donated red blood cells Anti-B with B antigen antibody Transfusion Complement Hemoglobin Agglutination and complement binding Hemolysis Group Questions 1) You get into a car accident. At the hospital they need to give you blood but don’t know your blood type. What should the hospital do to save your life? 2) You have an infection. Describe a direct antibody test and an indirect antibody test you could use to confirm you have this infection.  Rh antigen common to red blood cells of humans and rhesus monkeys. About 85% of humans are Rh positive (Rh+) Rh– woman carrying an Rh+ fetus may be at risk for hemolytic disease of the newborn RhoGAM administered to prevent hemolytic disease of the newborn  Drug-induced cytotoxic reactions can occur when drug molecules bind larger molecules and stimulate the production of antibodies. Can lead to various diseases Immune thrombocytopenic purpura Agranulocytosis Hemolytic anemia Type III (Immune Complex–Mediated) Hypersensitivity Caused by formation of immune complexes Can cause localized reactions Hypersensitivity pneumonitis Glomerulonephritis Can cause systemic reactions Systemic lupus erythematosus Rheumatoid arthritis Type III (Immune Complex–Mediated) Hypersensitivity Caused by formation of immune complexes Can cause localized reactions Hypersensitivity pneumonitis Glomerulonephritis Can cause systemic reactions Systemic lupus erythematosus Rheumatoid arthritis  Hypersensitivity pneumonitis occurs from inhalation of an antigen into the lung. Subsequent inhalation of the same antigen results in formation of immune complexes activates complement and starts an immune reaction. Farmers lung, librarians lung, mushroom growers lung – often associated with the workplace because repeated exposure is necessary. Rheumatoid arthritis immune complexes deposited in the joint resulting degradation of the joints Results in release of inflammatory chemicals The joints begin to break down and become distorted Trigger not well understood Treated with anti- inflammatory drugs  Systemic lupus erythematosus is a condition when autoantibodies against DNA result in immune complex formation. Many other autoantibodies can also occur Against red blood cells, platelets, lymphocytes, muscle cells Trigger unknown Immunosuppressive drugs reduce autoantibody formation Glucocorticoids reduce inflammation Type IV (Delayed or Cell-Mediated) Hypersensitivity Inflammation 12 to 24 hr after contact with certain antigens, not an antibody mediated response. Response is due to interaction of antigen, antigen-presenting cells, and T cells. Delay reflects the time it takes for macrophages and T cells to migrate to and proliferate at the site of the antigen. One example of this is the tuberculin response. An injection of tuberculin beneath the skin causes reaction in individuals exposed to tuberculosis or tuberculosis vaccine Determines if someone has developed an immune response to the bacterium that causes tuberculosis Used to diagnose contact with antigens of M. tuberculosis No response when individual not infected or vaccinated Red, hard swelling develops in individuals previously infected or immunized  Allergic contact dermatitis is another Type IV (delayed response). Cell-mediated immune response Results in an intensely irritating skin rash Triggered by chemically modified skin proteins that the body regards as foreign Acellular, fluid-filled blisters develop in severe cases.  Graft rejection is another type of Type IV (Delayed or Cell- Mediated) Rejection of tissues or organs that Hypersensitivity have been transplanted Grafts perceived as foreign by a recipient undergo rejection Immune response against foreign MHC on graft cells Rejection depends on degree to which the graft is foreign to the recipient Based on the type of graft  Graft-versus-host disease is when the body rejects a transplant. Donated bone marrow cells Lymphoma is cancer of the bone marrow treat regard patient’s cells as foreignirradiating the body to kill all bone marrow c Donor and recipient differ in drugs Irradiation MHC class I molecules Grafted T cells attack the recipient’s tissues Donor and recipient differ in MHC class II molecules Grafted T cells attack the host’s antigen-presenting cells Preferable grafts are from siblings or a parent because they will have a lower chance of rejection Immunosuppressive drugs can stop graft-versus- host disease Glucocorticoids – (corticosteroids or steroids) suppress the response of T cells to antigen Cytotoxic drugs – block cell division by blocking mitosis this can have a more profound effect on lymphocytes Cyclosporine – prevent interleukins and interferons by T cells, this prevents T cell growth Lymphocyte-depleting therapies – Take home messages There are four types of immune hypersensitivities 1) Type 1 Immediate what most people think of as allergies generally treated with steroids and antihistamines 2) Type 2 Results when cells are destroyed by an immune response, for example a blood transfusion with an incompatible donor 3) Caused by formation of immune complexes with antigen – can be caused by repeated exposure to antigen or in the case of systemic conditions (Arthritis) we don’t know what causes it. 4) Delayed or Cell mediated – cell mediated, the delay is caused by the time needed for T cells to migrate to the site of the antigen (graft vs host) usually treated with steroids or immunosuppressive drugs Outline History of Immunization Active vs Passive Immunization Immune Testing Hypersensitivities Autoimmune diseases Immunodeficiency diseases (primary vs acquired)  Autoimmune Diseases are when the bodies immune system attacks itself. People really don’t know where these diseases come from. Estrogen may stimulate destruction of tissue by cytotoxic T cells Some maternal cells may cross the placenta and trigger autoimmune disease later in life Environmental factors include viral infections Genetic factors include certain MHC genes T cells may encounter self-antigens that are normally “hidden” – sperm for example Microorganisms may trigger autoimmunity because of molecular mimicry Failure of the normal control mechanisms of the immune system  There are two major categories of auto immune diseases Systemic autoimmune diseases attack multiple organ systems. (lupus) Single-organ autoimmune diseases attack a single organ.  Single-organ autoimmune diseases attack a single organ. Single-organ autoimmune diseases Autoimmunity affecting blood cells -- hemolytic anemia Autoimmunity affecting endocrine organs -- Type I diabetes mellitus Autoimmunity affecting nervous tissue – multiple sclerosis (MS) Autoimmunity affecting connective tissue – rheumatoid arthritis  Immunodeficiency diseases caused by a defective immune system can either be primary or acquired. Primary Result from some genetic or developmental defect Develop in infants and young children Many inherited defects in all the body’s lines of defenses Chronic granulomatous disease ( can’t make reactive oxygen species) Severe combined immunodeficiency disease (SCID) (bubble boy) DiGeorge syndrome ( failure of the thymus to develop) Bruton-type agammaglobulinemia ( cannot make immunoglobins)  Acquired immunodeficiency diseases can result from a number of different causes. Severe stress Excess production of corticosteroids suppresses cell-mediated immunity Malnutrition and environmental factors Inhibit production of B cells and T cells Acquired immunodeficiency syndrome (AIDS) Opportunistic infections, low CD4 cells, presence of HIV Acquired Immunodeficiency Syndrome (AIDS) Opportunistic infections, low numbers of CD4 cells, presence of HIV make it so that infections that are normally not existent or not very dangerous are life threatening. First recognized in young male homosexuals in the U.S. and now found worldwide HIV in blood, semen, saliva, vaginal secretions, and breast milk concentrated enough to cause infection Must be injected into the body or contact a tear or lesion in the skin or mucous membranes Eastern Europe Western & Central Asia and Central 1.5 million North America Europe East Asia & Pacific 1.4 million 850,000 850,000 South & Caribbean North Africa Southeast Asia & Middle East 3.8 million 240,000 310,000 Latin America Sub-Saharan 2 million Africa 24.4 milion Australia & New Zealand 59,000  Certain behaviors make contacting AIDS more likely. HIV is transmitted primarily via sexual contact and intravenous drug use HIV is also transmitted across the placenta and in breast milk Certain behaviors increase the risk of infection Anal intercourse Sexual promiscuity Intravenous drug use Sexual intercourse with anyone engaging in the previous three behaviors Figure 18.19 The course of AIDS Opportunistic Death Primary infection diseases HIV RNA copies/ml plasma Clinical latency CD4 T cells/mm3 blood Weeks Years HIV in blood CD4 (helper) T cell count Antibody against HIV  Replication of HIV 1) Attachment to help T cell 2) Entry and uncoating 3) Synthesis of DNA 4) Integration 5) Synthesis of RNA and polypeptides 6) Release 7) Assembly and maturation  HIV ssRNA genome must be made into dsDNA by reverse transcriptase. dsDNA is then be integrated into the genome of the helper T  So why has AIDS been such a difficult disease to treat or develop a vaccine? 2 copies of its genome – allows for frequent mutation Targets helper T cells, macrophages, and dendriticOver 100 vaccines have been brought cells thus it kills the very clinical trail over the last 30 years. cells that could help destroy it. Antigenic variability allows for evasion of the host immune system http://www.sciencealert.com/a-new-aids-vaccine-is-about-to-be-trialled-in- humans-for-the-first-time Take home messages Autoimmune diseases are when the body attacks itself, immune deficiency diseases are when the immune system has been weakened by genetic disease (primary) or outside insult (acquired). No one really knows why a individual contracts an autoimmune diseases but there are numerous potential avenues. AIDS is caused when the HIV virus attacks members of the immune system. HIV has been difficult to treat because it can mutate quite quickly thus it is not effected by typical vaccine methodologies. Group Questions 1) Describe how type III and type IV immune reactions differ from one another. 2) How does an autograph differ from an allograph. Why are immunosuppressive therapies bad for you. What precautions should you take when undergoing such therapies?