BOIM 250n 1st Edition Lecture 22Outline of Last Lecture I. Cytotoxic T cellsII. Extracellular Killer CellsIII. ADCCIV. CytokinesV. Immunological MemoryVI. Types of Adaptive ImmunityOutline of Current Lecture I. Immunologic-based TestsII. Hypersensitivity ReactionsCurrent LectureI. Immunologic-based testsa. Monoclonal antibody very useful in testsi. Uniform in size and shapeii. Highly specific to a single antigen iii. Can be produced in large quantitiesb. Agglutination tests i. An antibody can bind to particulates or cells so that you can read results via the eyeii. If antibody and cells with antigens are placed together the antibody will link the cells into clumpsiii. Used for testing the presence of antibody and titer of antibody in the bloodiv. Can also be used with a soluble antigen linked to beadsc. Enzyme-linked immunosorbent assay (ELISA)i. Immunosorbent means an antibody will be involved—which implies an antigen will also be involvedThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.ii. Direct ELISA example:1. Antibody is bound to a well in a plate2. Place the solution with the antigen in the well and wash out excess3. Same antibody linked with an enzyme is placed in the well4. Enzyme substrate added and bound enzyme produces color5. Color indicates a positive testiii. An example of an ELISA is a pregnancy testII. Immune Disorders: Hypersensitivity Reactionsa. Hypersensitivity—also called an allergyi. Defined as an immune reaction outside of the normal rangeii. Happens when you are sensitized to an antigen by previous exposureiii. Next exposure causes a more vigorous immune response—may be damagingb. 4 types of hypersensitivity reactions:i. Type 1: anaphylactic1. Can have symptoms in less than 30 minutesii. Type 2: cytotoxic1. Can have symptoms in 5-12 hoursiii. Type 3: immune complexiv. Type 4: delayed cell-mediated1. Symptoms may arise around a dayc. Type 1: Anaphylactici. Fast acting responseii. Can be deadly—anaphylactic shockiii. Must first be sensitized to the antigen (allergen)iv. IgE is sometimes produced1. IgE is a very rare antibody because it is so reactivev. IgE can be bound to a basophil or Mast cell by and Fc receptorvi. When allergen binds 2 or more adjacent IgE’s it causes degranulation of the cell which releases histamine and other mediatorsvii. Other effectors are:1. Leukotrienes: cause smooth muscle contractions (bronchial spasms during asthma)2. Prostaglandins: affect smooth muscles of respiratory system and causes mucus secretionviii. Systemic Anaphylaxis—anaphylactic shock:1. Injected antigens are more likely to causes this than by other exposures2. Rapid drop in blood pressure because peripheral blood vessels enlarge3. Can cause swelling of tissues including in respiratory tissues4. Treated with injected epinephrine—epinephrine constricts the blood vessels5. Reminder: shock is defined by a significant loss of blood pressureix. Localized anaphylaxis:1. Usually from ingested or inhaled allergens2. Symptoms dependent on route of exposurea. Upper respiratory: hay fever; itchy eyes; nasal congestion; sneezingb. Lower respiratory: asthma; constriction of smooth musclesin bronchial tubesc. Food allergies: if surface contacted then hives are a common reactioni. If ingested can cause systemic anaphylaxis3. 8 foods are responsible for 97% of all food allergies (eggs, peanuts, tree nuts, milk, soy, fish, wheat and peas)4. Food intolerance is a different syndrome (lactose intolerance)5. There are about 200 deaths/year in the US that are caused by severe food allergiesx. Prevention of anaphylaxis: 1. Skin test to identify allergensa. Used to determine exactly which allergen is responsibleb. Small amount of possible allergens injected just beneath the skinc. Sensitivity indicated by rapid inflammatory reactioni. Produces redness, swelling, itching at injection site2. Desensitization a. Series of gradually increasing doses of allergen injected beneath the skinb. Hopefully IgG will be produced rather than IgEc. Hopefully IgG will neutralize the allergen before in binds tocell-bound IgEd. Inhaled allergens: 65-75% effectivee. Insect venom: up to 97% effectived. Type 2: Cytotoxic Reactionsi. Involve activation of complement by IgG or IgM bound to an antigenic cell1. Can be foreign cell or host cell with foreign antigen on its surfaceii. Ex: transfusion reactions:1. Human blood is grouped in 4 ABO blood type groups2. Based on carbohydrate antigens on the red blood cell surfaceiii. People with specific blood types can make antibodies against other types1. So if a person with type A blood gets transfusion of type B blood then anti-B antibody can bind to transfused red blood cells2. Complement binds to antibody on red blood cells and lyses cell3. VIEW TABLE 19.2 IN