PSIO 431 Exam 3

Define 'herd immunity.'

*TEST QUESTION herd immunity: amount of people in a population that are vaccination herd effect: need vaccination rate near 90% to get protection of those who are not vaccinated

Rh

*second most important blood group system -Rh = antigens that are on proteins D = Rh positive = Rh(D) positive -D is dominant over d --> (+) as DD and Dd *you dont make antibody to RhD if youre Rh(D)- and you become immunized with Rh(D)+

Describe tests that are used for determining if a patient has antibody to a soluble or particulate antigen.

-Agglutination titer -Immunodiffusion -Immunofluorescence -ELISA

Define heterophile antibody, and identify a common disease in which one type is increased enough to be useful diagnostically.

-Antibodies to one antigen can bind to another (aka cross-reactive antibodies) ex: ab in a patient with infectious mononucleosis --> cross reacts well with horse RBC ex: ab people with syphilis make --> cross reacts with phospholipids with beef heart *gives us a cheap and quick reaction to test

Explain the ABO antigen situation in a person of Bombay blood type, and the consequences of a transfusion of non-Bombay blood into such a patient.

-Bombay people would type as O even though theyre not O -can only transfer bombay blood

A patients serum contains cryoglobulin (define it). You centrifuge it and now want to know if it's mixed or monoclonal. What should you do?

-Cryoglobulin is the white, fluffy ppt that forms after refrigeration if Ag-Ab complexes are present in serum. -To determine if it's mixed or monoclonal, do electrophoresis and then specific Ab tests.

Distinguish between direct and indirect immunofluorescence techniques.

-Direct techniques test for the presence of Ag -Indirect techniques test for the presence of Ab: 1. A smear of the suspect bacterium, grown in culture, is prepared 2. The pt's serum is layered over it 3. Fluorescein-labeled goat anti-human Ig is added and looked at under a microscope by UV light. *If the bugs fluoresce, there was antibody in the serum.

Discuss the role of Tfh in the persistence of HIV latency and active infection.

-During the long seropositive period, ►the major site of HIV persistence is memory Tfh cells in the lymph nodes. -Tfh cells are able to suppress viral replication but not eliminate the virus DNA from their nuclei. -If a virally infected Tfh gets activated by its correct Ag, it will develop into a clone of virus-producing cells. -This disruption of Tfh function leads to, or is accompanied by, a gradual dysregulation of B cells, which early on can be hyperactivated, and later become exhausted so that antibody production begins to decline.

Describe tests to evaluate T cell numbers and function in the lab.

-Fluorescent cells can be counted under a microscope that has a UV light source and appropriate filters, or by flow cytometry. -Stimulate T cells in mononuclear leukocyte preparations (lymphocytes + monocytes) with the T cell mitogens PHA or Con A, and observe either proliferation or IL-2, IL-4, or IFNγ production. -In infants, a chest x-ray may be very useful; how does the thymus look -Lymphoid biopsy may be necessary in suspected primary immunodeficiency.

Discuss the pathogenesis of AIDS, including target cell types, latency versus productive infection.

-HIV-1 is the most antigenically variable pathogenic virus -After a single exposure, infected people develop high blood virus levels (>105 copies/mL) that peak at about 6 weeks -Loss of CD4 cells in the gut mucosa, and an associated increase in gut permeability -Ab to HIV peaks by 9 weeks, whereupon virus levels fall sharply, but not to zero = pts "set point" -The mean incubation period (infection to AIDS) estimated from transfusion-acquired HIV infection, where it could be most precisely timed, it was about 9.5 years without treatment. -Reverse transcriptase is a highly error-prone enzyme, without proofreading capability, so infected people have many variants in their body

Name the virus that causes AIDS, and its classification.

-HIV-1 subtype C = Human Immunodeficiency Virus dominating current epidemic -Part of the lentiviruses group -A nontransforming retrovirus, that is, an RNA virus that carries no oncogene, and reproduces itself by copying its RNA into DNA by means of its own enzyme, reverse transcriptase.

Describe in principle the ELISA test. Diagram the reactions involved when the simple ELISA is used to measure antibody, and to measure antigen.

-If an Ag is at least divalent, a sandwich or capture ELISA is used to measure its concentration. 1. Couple Ag to a plate 2. Add pt. serum 3. Add second Ab that has an enzyme coupled to it (usually peroxidase). Adding a colorless substrate for the enzyme will produce a colored product that can be visualized 7. Measure the intensity of the product color in a plate spectrophotometer, also called an ELISA reader.

Where does the majority of HIV replication occur?

-In the B-cell follicle of the Tfh cells (even though most T-cells are on the peripherally of the follicles

Define and discuss "long-term survivors" and "elite controllers" in HIV infection.

-In the years before the first HIV drug (1981-1987) 95% of all infected people died of tumors or opportunistic infections. -LTS were those who had a 32-base pair deletion in the gene for a chemokine receptor, CCR5 (they were CCR5Δ32) -Other LTS were "elite controllers." They became infected but did not progress to AIDS. Two-thirds of them have the HLA-B57 allele. They make effective CTL to HIV peptides presented in HLA-B57.

Discuss the types of infections seen in AIDS patients, and provide an immunological basis for this spectrum.

-Infections are primarily of types that require T cell-mediated immunity, as might be expected given the virus' primary target. -Viral infections, including CMV, hepatitis and especially herpes simplex/zoster -Fungi especially Candida albicans of the mouth, esophagus, or rectum and and Pneumocystis jirovecii -Protozoan infections, such as Toxoplasma, Cryptosporidium (which causes a sometimes-fatal diarrhea), and Isospora are very serious. -Opportunistic intracellular bacteria⎯usually Mycobacterium avium complex (MAC), and more and more commonly, M. tuberculosis -Kaposi sarcoma: a tumor of the endothelial cells lining lymphatics. It is caused by KSHV (Kaposi's sarcoma herpesvirus,) also called HHV8 -Burkitt lymphoma

Discuss the origin of the AIDS virus and the origins of the current epidemic.

-It is thought that HIV-1 evolved recently from SIV, perhaps as recently as the 1940s in Zaire (now the Democratic Republic of Congo). -The first sera in the USA with antibody to HIV-1 are found in 1978; in Africa, some sera from 1959 are positive

What is a mitogen?

-Mitogens are plant (usually) proteins that bind certain sugar sequences; they are probably part of the plant's defense system against things like fungi. -Some of these sugar sequences are also found on human cells; ConA and PHA both bind sugars associated with the T cell receptor complex, fooling T cells (all of them!) into thinking they are recognizing antigen.

What is the difference in a monoclonal vs. polyclonal pathology as seen in the serum protein electrophoresis?

-Monoclonal pathologies result in a narrow, spike-like gamma globulin peak due to a clonal process that is malignant or potentially malignant (myeloma, leukemia) -Polyclonal pathologies have a large, broader than normal gamma peak due to any reactive or inflammatory process with Abs produced, and they usually are associated with nonmalignant conditions (bacterial infection).

Discuss the prospects and problems of AIDS vaccine development.

-Need a vaccine that can preferentially stimulate Th1 cells and CTL; the current vaccines seem to be best at inducing antibody responses, and antibody doesn't protect very well (otherwise, seropositive people wouldn't get sick)

Explain the difference between "HIV-seropositive" and "AIDS"

-People are 'seropositive' if they have antibody to HIV, which is the most common way in which infection is first detected -AIDS is when Th (CD4+) cells fall below 200/μL of blood (Normal range: 500-1000/ μL)

For persons of the A, B, AB and O blood groups, give the following data: most and least common groups; red cell antigens; specificities of the ABO antibodies in their plasma; safe donors to that type; safe recipients of blood from that type; possible genotypes.

-Red cells dont carry MHC antigens in humans --> antigens are much less polymorphic in the population -platelets do bear HLA (Class I) --> can cause alloimmunization problem GROUP O -defined by H antigen -"amorph": doesnt code for working transferase --> group O only have basic Core (H antigen) -best for blood donors = O- GROUP A -defined by A antigen GROUP B -defined by B antigen GROUP AB -have both A and B antigens on the red cells; 1/2 have circle 1/2 have square -rarest BOMBAY: people dont have the H at the end --> A and B and O are all foreign -truncated version of the H antigen *need the H substance to add on the final sugar (square or circle) that defines which group you are -everyone has H antigen

Describe flow cytometry.

-Take cells in suspension and pump them through an orifice so small that the cells emerge in single file stream. -Lasers illuminate the cells and light emitted or scattered by each cell is collected by photomultipliers -Light scatter gives information about cell size and cytoplasmic granularity, and if the cell has bound a fluorescent-tagged antibody, the fluorescent light emitted is quantified. -By using multiparameter cytometry, you can ask questions like, what percentage of cells in the blood bears the CD34 marker that is seen on hematopoietic stem cells? Are they cycling or resting? *The machine examines 10,000 individual cells in a second.

Describe a test which can be used to evaluate T cell immunocompetence in a clinic or on the ward.

-The best overall test (for Th1 activity): skin test with common antigens to which most people will have DTH -A good set is: Candida, streptokinase/streptodornase (SK/SD,) trichophytin, mumps, tetanus, tuberculin. -Read at 24-48 hours.

Discuss the advantages of passive agglutination (e.g., with antigen-coated latex particles) over precipitation, and outline the technique.

-The bigger the effective size of the antigen, the more sensitive the agglutination test bc it is easier to detect ppt sooner. 1. Couple Ag to latex beads in various dilutions in separate test tubes 2. Add pt's serum to the various dilutions and look for agglutination 3. The titer is the reciprocal of the highest dilution that will agglutinates

What are the pros and cons of serum protein electrophoresis?

-This is cheap (around $40) and easily quantified -Not very sensitive to small abnormalities. For example, it could not pick up selective IgA deficiency, because IgA runs pretty much together with the much larger IgG (γ globulin) band.

What are some of the barriers to HIV vaccine development?

-Variability of the virus -Poor immunogenicity of the HIV envelope -Masking of neutralizing epitopes -Lack of animal model -Logistical issues in performing human trials of HIV vaccines

Discuss possible reasons for which the total number of CD4 cells in AIDS patients decline.

-With time, CD4 cells are gradually lost; it looks like simple exhaustion of the ability to make more of them. -This is commonly expressed as a falling blood CD4/CD8 ratio (the normal ratio is from ~1.5 to 3). -An accelerating fall in this ratio, or an absolute CD4 count below 400/μL, are poor prognostic signs. -When the immune system can no longer cope, opportunistic infections take hold.

What are disadvantages of ELISA tests?

-You can have cross-reactive Abs that would result in a false positive. -Small molecules, with only one epitope, can't be measured in a capture assay.

Discuss the incidence of selective IgA deficiency and associated features seen in those that are symptomatic.

-most common antibody deficiency -usually asymptomatic; may have diarrhea, sinopulmonary infections, increased allergies and autoimmunity -some familial tendency -more common in those with celiac disease

Define the crossmatch, and explain why it is important. Explain how red cells are destroyed following a mismatched transfusion, and why this may be devastating to the recipient

-prior to transfusion, recipients are typed for ABO and Rh -> screen for expected and unexpected antibodies *must be compatible at ABO and Rh MAJOR CROSSMATCH: worst case scenario --> generalized complement mediated hemolysis --> free hemoglobin deposits in the kidney --> acute renal failure *crossmatch is a test where plasma from prospective recipient is mixed with RBC for donor -no hemolysis/agglutination : compatible O- = universal donor AB+ = universal recipient

Types of Vaccines

1) LIVE ATTENUATED: [use when can attenuate] -Pro: All innate immunity engaged; robust cellular (CD4/CD8) + humoral responses; Longer lasting humoral response w/ high titer + affinity. -Con: Higher risk of adverse events (reversion to virulence); *infectious: can spread to other people but will protect host; Increased contraindications in pop (Vaccinia + atopic dermatitis); Production cost + stability-cold chain; Not all agents can be attenuated (HIV, malaria) 2) WHOLE KILLED VIRUS/BACTERIA [when cant attenuate] -Pro: Endogenous ligands/agonists for innate receptors (PAMPS) produces innate activation; Strong humoral response --> good CD4 T cell help; cellular response + reaction isnt as bad because less of a response -Cons: Higher risk of adverse events-strong local toxicity; "Reactogenicity"; Substantial loss of CD8 response; Production cost + stability Salk vaccine: [whole killed] high safety; produces IgG (bad: no IgA in gut, virust still replicats in host and can spread to other, protection = short lived, no cellular immunity) Sabin virus [live attenuated] Live infection in gut. Forms cellular + humoral immunity --> longer lived. Forms protective IgA --> blocks spread of WT polio. Vaccine strains shed from host and can provide "herd" immunization SUBUNIT: [using only components/subunits of infectious agent in vaccine form] -Pros: Sufficient humoral responses., Fewer reactogenicity + toxicity issues, Lower production cost, increased shelf life. -Cons: Little/no cellular responses; CD4 responses inferred by class switched antibody; Requires more frequent boosting; Requires adjuvant: reduced innate activation

What are the 8 steps that must occur to get a positive DTH skin test?

1. Ag is endocytosed by DCs 2. Ag is digested with endosomes by lysosomal enzymes 3. Ag. is loaded into MHC class II and displayed on cell surface 4. Th1 anti-TB cells circulate around DCs 5. Th1 anti-TB cells recognize and bind MHC class II 6. Th1 cells are activated and secrete IFN-gamma 7. Macrophages are attracted by cytokines 8. Macrophages are activated and become M1 = angry macs = inflammation

Describe the procedure used in serum protein electrophoresis, and the underlying principles.

1. Apply serum to the gel wells 2. Apply voltage to gel: smaller proteins with migrate further from the anode through the gel (separation based on protein size and charge) 3. Stain proteins and their densities are calculated electronically to provide graphical data on the absolute and relative amounts of the various proteins. 4. Scan gel to get graphic representation of characteristic Ig peaks

Early in HIV-1 infection the virus uses the ___1___ coreceptor in addition to CD4, but later in infection timeline, the virus uses the ___2____ coreceptor more.

1. CCR5 2. CXCR4

Describe the concept of immunoediting.

1. Elimination - through immune surveillance. when a clone becomes malignant it is recognized and eliminated. This prolongs tumor growth 2. Equilibrium - tumor and lymphocytes exist in equilibrium (lymphocytes only kill a certain amount of the tumor) - EBV & Bone Marrow is an example. However, if there is an immunity drop for some reason, tumor cell reactivation can occur 3. Escape (tumor cell fights back) - Regressors and Progressors. 3 experiments

Describe the concept of immunoediting.

1. Elimination - through immune surveillance. when a clone becomes malignant it is recognized and eliminated. This slows tumor growth 2. Equilibrium - tumor and lymphocytes exist in equilibrium (lymphocytes only kill a certain amount of the tumor) - EBV & Bone Marrow is an example. However, if there is an immunity drop for some reason, tumor cell reactivation can occur 3. Escape (tumor cell fights back) - Regressors and Progressors. 2 experiments

What are some of the problems for HIV vaccine production?

1. HIV exhibits tremendous global genetic diversity. 2. Its immense mutational capacity allows evasion of both T and B cell immunity. 3. HIV goes latent in the host genome, from which it cannot be eliminated by conventional antiretroviral drugs. 4. There has been no known example of spontaneous immune clearance, to use as the basis for data-driven vaccine design. 5. Although bnAbs have been found, they are rare, only found in a subgroup, take years to develop, and are extensively hypermutated; no method exists now for induction of these Abs by immunization. 6. But a lot of smart people think that they can figure out a way to make these epitopes immunogenic in everybody.

Describe the steps involved in a sandwich ELISA

1. Make or purchase 2 monoclonal Abs to the Ag of interest (each to a different epitope on that Ag) 2. Put one of the mAbs on the plate so that it is stuck to it 3. Add pt's serum to the plate 4. Wash off anything not bound 5. Add second mAb which will bind with direct proportionality to the amount of Ag present 6. The second mAb has an enzyme coupled to it (usually peroxidase). Adding a colorless substrate for the enzyme will produce a colored product that can be visualized 7. Measure the intensity of the product color in a plate spectrophotometer, also called an ELISA reader.

Discuss whether data from immunosuppressed and immunodeficient patients support the theory.

1. People with immunodeficiencies, particularly of T cells, have a higher incidence of tumors (skin cancers and lymphocyte cancers) 2. Activated T cells that recognize tumor-associated antigens can easily be identified. The presence of lymphocytes in a tumor (tumor-infiltrating lymphocytes or TIL results in a better cancer prognosis) 3. A small percentage of tumors, mainly melanomas and some lymphomas, spontaneously regress, presumably due to an immunologic response. 4. Nude mice don't thymus = no T-cells AND they don't get tumors, but they do have NK cells!

Discuss whether data from immunosuppressed and immunodeficient patients support the theory.

1. People with immunodeficiencies, particularly of T cells, have a higher incidence of tumors - Skin/Lymphoid cancers 2. Activated T cells that recognize tumor-associated antigens can easily be identified. The presence of lymphocytes in a tumor (tumor-infiltrating lymphocytes or TIL). Patients have a better cancer prognosis with these 3. A small percentage of tumors, mainly melanomas and some lymphomas, spontaneously regress, presumably due to an immunologic response. Nude mice don't have a thymus so no T cells. You would except higher cancer levels but they don't get any tumors. Possible due to the High NK cells

What are the 3 intracellular enzymes necessary for HIV replication, insertion into host genome, and spread?

1. Reverse transcriptase: transcribes viral RNA into ds DNA 2. Integrase: makes random cuts in host DNA and allows viral DNA to be inserted into the host genome 3. Protease breaks up viral proteins that can then go into new viral infections particles that bud off of the infected cell

Describe both the mode of entry of the HIV-1 virus into a cell, and the mode of exit

1. Virus enters body (90% via mucous membranes) and adheres to lectin on DCs (DC-SIGN) 2. DCs phagocytose virus and transport virus to the LN 3. HIV binds CD4 Th cells with its envelope glycoprotein, gp120 4. This induces a conformational change in gp120, which allows HIV to bind a co-receptor CCR5 or CXCR4 5. Binding CCR5 or CXCR4 induces a conformation change of the gp41 glycoprotein that is associated with gp120, exposing a very hydrophobic region that literally melts away the T cell's membrane, so the cell and virus fuse 6. The virus injects its core into the cell, activates its reverse transcriptase and make a double-stranded DNA copy of its RNA. 7. Viral integrase inserts random breaks in the hosts DNA where the viral DNA 8. HIV-infected T cells may die rapidly; become persistent virus-producers; or enter latency 9. When the virus is replicating, gp120/gp41 is made early, and it becomes inserted into the cell's plasma membrane. ►This allows fusion of the infected cell to nearby uninfected CD4 cells, and a syncytium forms. In this way the virus can spread without an extracellular phase.

Discuss the serum protein electrophoretic pattern which would be expected if a patient: A. was normal B. had selective IgA deficiency C. had multiple myeloma D. had severe pyogenic (pus-producing) infections E.was hypogammaglobulinemic

A. Would have regular /intermediate sized gamma globulin peak (farthest to the right) B. it could not pick up selective IgA deficiency, because IgA runs pretty much together with the much larger IgG (γ globulin) band. So it would appear normal C. A homogeneous narrow spike-like peak in a focal region of the gamma-globulin zone D. Would have homogenous larger gamma globulin peak (hypergammaglobulinemia) E. Would be missing gamma globulin peak (Bruton's agammaglobulinemia)

Adjuvant Examples

ADJUVANT: ingredient of a vaccine; helps create a stronger immune response + work better Live attenuated -Measles, Mumps, Rubella, smallpox (vaccinia), VZV, . Whole killed -Rabies, whole cell pertussis (wP), inactivated polio virus (IPV) Subunit -DPT, HPV, pneumococcal polysaccharide (and protein conjugate), Influenza.

Identify those organisms against which cell-mediated and humoral immunity is most effective.

ANTIBODY/HUMORAL IMMUNITY *prevents you from getting something, once you have it, you need cellular -Inhibits binding to host cells (prevents entry) -Promotes uptake by macrophages -Lysis -pro: can prevent illness; easier to induce -con: organisms mutate surface; no access to intracellular; prevents but does not clear CELL MEDIATED Destroy pathogen (neutrophils, activated macrophages) Inhibit growth (interferons) Kill infected cells -Pro: targets internal, more conserved antigens across numerous strains, can eradicate intracellular pathogens, therapeutic -Con: requires actual infection; harder to induce Live attenuated: gives you all --> innate Whole killed--> doesnt give you all Adjuvent --> mostly just B cell help

State the concept of the Immune Surveillance theory.

Adaptive immune response evolved to detect changes in body's cell surface due to damage or mutation True role = constantly monitor surfaces of cells in the body, once detected, destroy

State the concept of the Immune Surveillance theory.

Adaptive immune response evolved to detect changes in body's cell surface due to damage or mutation not necessarily foreign pathogens True role = constantly monitor surfaces of cells in the body, once detected, destroy

3.Describe tumor-associated antigens (TAA), and compare and contrast TAA from viral, mutant, and normal gene products.

All tumor cells have antigens that are not readily found on the corresponding normal cell, If we could figure out what antigen is seen in each tumor, we can get patients to see it and attack it TAA - Viral - 20% caused by viruses (ex. HPV) Mutant Gene Products - Chemical and physical carcinogens lead to cellular transformation - patient specific Normal Gene products - Oncofetal antigens, Differentiation Antigens, Clonal Antigens

Describe tumor-associated antigens (TAA), and compare and contrast TAA from viral, mutant, and normal gene products.

All tumor cells have antigens that are not readily found on the corresponding normal cell, If we could figure out what antigen is seen in each tumor, we can get patients to see it and attack it TAA - Viral - 20% caused by viruses (ex. HPV) Mutant Gene Products - Chemical and physical carcinogens lead to cellular transformation - patient specific Normal Gene products - Oncofetal antigens, Differentiation Antigens, Clonal Antigens

8. Discuss the principles underlying antibody or T cell methods that might be used as treatments of tumors.

Antibody to TAAs should be useful. mAb can be used as-is, or they can be tagged with a poison such as ricin, or diphtheria toxin, or a radioisotope. Another approach is to use antibodies to growth factors or their receptors to try to inhibit autocrine (self-stimulating) tumors; one example is anti-IL-2 receptor in T lymphomas; ~ Herceptin, a mAb to the HER2 surface growth stimulatory molecule on some breast cancers is available

9. Describe a mechanism by which BCG treatment causes tumor regression.

BCG is injected directly into the tumor. A ferocious delayed-type hypersensitivity reaction to BCG ensues, and the tumor cells are killed the way lung is killed in TB. This is used to some degree in cutaneous tumors like melanoma, and ►BCG instilled directly into the bladder is the treatment of choice for superficial bladder carcinoma.

Explain the situation in which ABO hemolytic disease of the newborn can occur.

Baby is RhD+ and mom is RhD-

Describe the laboratory diagnosis of AIDS.

CD4+ Tcell count < 200

Define carcinoembryonic antigen (CEA) and discuss its usefulness in screening for, diagnosis, and follow-up of colon cancer.

CEA is found in blood of patients with colon cancer and other cancers. Commercially available kits to detect CEA i blood Should not be used routinely because of many false positives Proper use of CEA measurement comes when there is a high suspicion of colon cancer or when cancer has been removed to confirm complete excision

Compare and contrast the techniques of the direct and indirect antiglobulin tests and the questions they are designed to answer.

COOMBS TEST: uses antibody against human Ig to detect human Ig on surface of RBC [direct] or plasma [indirect] DIRECT -is there Ab already on the cells? -rinse off the cells, add antiglobulin *detects cells that were coated with Ab in vivo INDIRECT -is there unexpected Ab to red cell antigens in the plasma of the recipient -take RBC, add plasma of donor, rinse cells, add antiglobulin -->if agglutinate there is Ab to them in the plasma (antiglobulin alone wont react with red cells)

Compare and contrast the roles of CTL and NK cells in killing tumors cells, with special reference to the amount of MHC Class I expressed by the tumor.

CTL - most important cell in tumor resistance. Can recognize TAA on MHC1. Activated TAA T cells migrate to tumor and can kill by inducing apoptosis. It also secretes IFNγ to stimulate MACs NK cell kills by ADCC if Antibody was made ~Can bind to alternative receptors that allow them to see cells that down regulate MHC1 ~Good at detecting stress proteins ~Can kill your cell or activate Apoptosis ~5% of blood lymphocytes ~Get inflammation so bringing in MACs (can kill tumors if M1)

What is passive agglutination?

Coupling Ag to larger particles (such as RBCs or latex beads) to have a more sensitive agglutination test.

Compare the roles of cell-mediated and humoral immunity in virus infections with regards to: preventing the infection; controlling spread of viruses in the body; which is responsible for recovery from disease; how each can cause immunopathology.

DAYS 1-3 [Innate immunity] -recognition by PRR/TLR to PAMPS/DAMPS --> release of cytokines, chemokines, neutrophils, macro --> inflammation -viruses taken up by DC and will get presented to T cells DAYS 4-6 [transition/expansion] -DC present antigen to B and T cell in nodes --> proliferate --> leave thru blood once mature --> circulate -MCHI +MCHII recognizing + becoming M1 and M2 DAYS 7-10 [adaptive immunity] -T + B cells activated; T will match the antigen --> multiple --> lots of T cells -B cells --> producing antibodies and tagging everything

Describe the clinical features which, although not immunological, are part of DiGeorge syndrome.

DiGEORGE SYNDROME -large deletion on chromosome 22 --> thymus doesnt develop appropriately --> T cell immunodeficiency -parathyroid may be affected --> unexplained convulsions in infants that are controlled by Ca -vessels of heart develop abnormally -viral/fungal infections = common -clinical: Hypertelorism, down slanting eyes, fishmouth deformity, micrognathia, low set ears

7. Summarize the Hellstrom experiments using cells from tumor- bearing and cured patients to kill tumor target cells. Indicate which patients had blocking factors. Discuss the possible nature of blocking factors.

EXPERIMENT 1: T cells from the blood of regressors were added to a layer of melanoma cells growing in culture. Result: The T cells killed the tumor cells. EXPERIMENT 2: T cells from patients with progressively growing tumors were added in culture to melanoma cells, as a control. Result: The T cells killed the tumor cells. Conclusion: Surprise! The tumor cells in the patient somehow learned to "escape" EXPERIMENT 3: T cells from either group were added to melanoma cells, as before, but now in the presence of serum from progressor patients. Result: Now, no killing. Conclusion: The serum contains blocking factors. These were shown to be specific, only blocking the killing of melanoma cells by melanoma-specific killer T cells.

T or F? For most HIV infected pts, the use of one antiretroviral medication in the best way to care for them.

False. Sustained viral suppression requires multiple drugs that act on may viral targets.

10. Discuss prospects and problems concerning the use of monoclonal antibodies in the diagnosis or treatment of cancer.

Figuring out ways to activate innate immune cells to the tumor antigen and then reintroducing them to the patient

Describe the contents and routes of administration of commercial gamma globulin (IVIG) and indicate the conditions in which it can be useful replacement therapy.

Human immunoglobulation --> used for B cell deficiency (IG via IV or SC) IVIG every 3-4 weeks SCIG every 1-2 week

Discuss the use of IgG and IgM antibody titers in the diagnosis of intrauterine and neonatal infections.

IgG = Mom's ; will protect baby in utero and a little after; baby will make it later on IgM = baby's; can make in utero: *IgM = baby has it; IgG = maybe from mom

Discuss single radial immunodiffusion, with regard to the types of antigens that can be quantified with it, and the way that quantization is done.

Immunodiffusion can be used to measure any other multivalent antigen (one that can form a precipitate with an appropriate antibody), for example if you have a specific antiserum. 1. Cut a well in the center of a gel containing Ab to an specific Ag. 2. Load Ag into well and see how far it diffuses 3. Approximate the concentration of Ig in the serum added to the well based on comparing diffusion to a standard plate

Name the antibody class of most ABO isohemagglutinins.

Isohemagglutinins: antigens to the ABO groups that we dont have in our RBC -we are all exposed to these sugars (A, B, O) --> and we make Ab to the sugars that are foreign to us -ex: A blood will make Ab to B but not A *dont make antibody to O -Iso are of the IgM class -If anti-b: can be AA or AO

Discuss the composition of a typical conjugate vaccine, and describe its mode of action.

MHC can only present proteins --> you need to conjugate polysaccharides to a protein to be displayed (bacteria have polysaccaride membranes --> need to be changed because has to be a protein to be presented)

Describe the immunological problem of the Nude mouse, and name the human immunodeficiency condition it resembles.

Nude mice: have a mutation in FOXN1 gene --> Fail to make thymic stroma and hair --> have no T cells are immunologically similar to those DiGeorge syndrome children with complete absence of a thumus

Explains the different classes of Normal Gene Products in association with TAA's

Oncofetal - Made in normal fetal tissue that can be reexpressed in the tumor. Kits are available to detect but many false positives Differentiation - Lineage-specific and can be greatly overexposed in tumors. Most frequently ID'd. (Breast & Ovarian Cancer has too much EGFR-2) Clonal - Expressed uniquely on the malignant clone. Idiotype of the surface immunoglobulin in B cell malignancies, or TCR in T Cell malignancies

Name the most common enzyme deficiency seen in cases of SCID. Discuss possible approaches to replacing this enzyme.

SEVERE COMBINED IMMUNODEFICIENCY DISEASES (SCID) [group of diseases] [T cell] -most commonly X linked --> defect in gene for common gamma chain that forms receptor for IL2 -all others are AR: ex: ADA deficiency --> accumulation of toxic adenosine metabolites --> inhibit DNA synthesis -low # of T cells (and possibly B and NK cells); block in the development of lymphoid stem cells and maturation -children w/o treatment can barely survive 1 year -lymphopenia of T cells, absent thymic shadow on X ray, small/absent tonsils/lymph nodes, low mitogen responses/serum IgGs BM transplant is only curative therapy --> better to transplant purified stem cells than whole marrow -can also get gene therapy with variable success

Draw an outline diagram of lymphocyte development. On the diagram, indicate locations of abnormalities of development in DiGeorge syndrome, severe combined immunodeficiency (SCID), X-linked (Bruton's) hypogammaglobulinemia, and common variable immunodeficiency.

SEVERE COMBINED IMMUNODEFICIENCY DISEASES (SCID) [group of diseases] [T cell] -most commonly X linked --> defect in gene for common gamma chain that forms receptor for IL2 -all others are AR: ex: ADA deficiency --> accumulation of toxic adenosine metabolites --> inhibit DNA synthesis -low # of T cells (and possibly B and NK cells); block in the development of lymphoid stem cells and maturation -children w/o treatment can barely survive 1 year -lymphopenia of T cells, absent thymic shadow on X ray, small/absent tonsils/lymph nodes, low mitogen responses/serum IgGs X LINKED (Bruton's) AGAMMAGLOBULINEMIA (XLA) [B cell] -boys have pre-b cells in BM but are deficiency in circulating B cells and Ab production -due to mutation in tyrosine kinase gene btk --> needed for B cell development beyond pre-B cell stage -recurrent sinopulmonary infections (sinusitis and pneumonia) and chronic infectious diarrhea -these ppl cant tolerate polio --> reason done use oral/live HYPER IgM SYNDROME: -people cannot class switch; have high levels of IgM; CD40L deficiency (X linked), CD40 deficiency (AR) *High or normal IgM *Other isotypes are low *Recurrent infections COMMON VARIABLE IMMUNODEFICIENCY (CVID) -B cells are ineffective at making Ab or IgG -milder than SCID --> usually diagnosed in 20s -at risk for recurrent bacterial infections (sinopulmonary); malignancy, autoimmunity DiGEORGE SYNDROME -large deletion on chromosome 22 --> thymus doesnt develop appropriatey --> T cell immunodeficiency -parathyroid may be affected --> unexplained convulsions in infants that are controlled by Ca -vessels of heart develop abnormally -viral/fungal infections = common -clinical: Hypertelorism, down slanting eyes, fishmouth deformity, micrognathia, low set ears TREATMENTS 1) isolation 2) prophylactic anti-microbials 3) Human immunoglobulation: B cell deficiency (IG via IV or SC): IVIG every 3-4 weeks; SCIG every 1-2 weeks 4) transplantation: thymus transplants for Digeorge patients; SCID: BM transplant is only curative therapy --> better to transplant purified stem cells than whole marrow

Identify the oral and parenteral polio vaccines by the names of their developers and discuss their relative advantages and disadvantages, and note which is currently used in the USA.

SUBQ: Salk vaccine: [whole killed] high safety; produces IgG (bad: no IgA in gut, virust still replicats in host and can spread to other, protection = short lived, no cellular immunity) -no IgE in gut --> can be infected w/o symptoms (carrier) *canr revert --> spread to other people but not infect self -currently used in USA ORAL: Sabin virus [live attenuated] Live infection in gut (no carrier). Forms cellular + humoral immunity --> longer lived. Forms protective IgA --> blocks spread of WT polio. Vaccine strains shed from host and can provide "herd" immunization -can revert; can infect self *foreign countries: do salk then sabin --> no reversion (to self) possible

Give an example of a human and an animal antitoxin; a toxoid; a killed virus vaccine; and a live virus vaccine. Identify the one which produces the longest-lasting immunity. Discuss possible hazards of each type of preparation.

Salk vaccine: [whole killed] high safety; produces IgG (bad: no IgA in gut, virust still replicats in host and can spread to other, protection = short lived, no cellular immunity) Sabin virus [live attenuated] Live infection in gut. Forms cellular + humoral immunity --> longer lived. Forms protective IgA --> blocks spread of WT polio. Vaccine strains shed from host and can provide "herd" immunization

Characterize the infections you would expect in a pure B cell deficiency and in a pure T cell deficiency.

T CELL DEFICIENCY -severe infections of intracellular pathogens: viruses, bacteria, yeasts, fungi -candida albicans, pneymocystis jirovecii -occurs when theres no development of the thymus B CELL DEFICIENCY -"high grade" [extracellular, pyogenic = pus-producing] bacterial pathogens -staphylococcus aureus, haemophilus influenzae and streptococcus pneumoniae -Agammaglobunemia causes no B cells or immunoglobulins *gut organisms can be abnormal in either type

What is the leading cause of death in people infected with HIV?

TB

What are the typical peaks expected in a serum protein electrophoresis

The pattern of serum protein electrophoresis results depends on the fractions of two major types of protein: albumin and globulins. 1. Albumin, the largest peak, lies closest to the positive electrode (left). 2. The next five components (globulins) are labeled alpha1, alpha2, beta1, beta2, and gamma (left to right).

Which organ is the only organ that would have CD4+ and CD8+ cells in it?

Thymus (during T-cell maturation/education T-cells go through a phase where they are double positive for CD4 and CD8)

What is single radial immunodiffusion used for?

To measure levels of individual immunoglobulin classes or subclasses i.e. "do you have an Ab to something?"

T or F? The Hiv-1virus is not hardy, and common disinfectants (alcohol, Clorox) kill it readily. Health care practitioners should use hepatitis precautions.

True

6. Describe the nature and therapeutic use of tumor-infiltrating lymphocytes, TIL, in adoptive cellular transfer therapy.

Utilizes cells from patient's immune system to destroy cancerous cells that can't be removed Immune cells from the tumor (TILs) are isolated and expanded in culture using IL-2. Then the patient's immune system may be partially destroyed by irradiation to make room. The new cells are then reintroduced into the immune-depleted patient to kill remaining tumor cells. Must be patient specific

Discuss reasons for the apparent ineffectiveness of antibody in HIV infection.

When the virus is replicating, gp120/gp41 is made early, and it becomes inserted into the cell's plasma membrane. ►This allows fusion of the infected cell to nearby uninfected CD4 cells, and a syncytium forms. In this way the virus can spread without an extracellular phase.

In Hemolytic Disease of the Newborn, explain: a. The consequences of severe hemolysis in the newborn. b. The way in which the mother becomes sensitized. c. The class of antibody to Rh(D) the mother makes. d. The consequences of sensitization to subsequent fetuses. e. The role of Rh-immune globulin.

aka erythroblastosis fetalis -occurs in RhD+ babies of RhD- moms -in last trimester and delivery, RBC from baby get into mom's circulation --> mom will make anti RhD -subsequent pregnancy w/ another RhD+ baby --> mom's Ab (from 1st pregnancy) can cross placent and destroy the fetus's RBC *w/ each pregnancy, response will increase -fetus will be born jaundiced --> dangerous because bilirubin can cross blood brain barrier and damage basal ganglia --> cerebral palsy or death PREVENTIBLE -at time of first (+) baby: if mom is given IgG ab to RhD --> Ab will opsonize RBC --> destroy before change to immunize her *she must recieve Rh IgG each time *perhaps give mom a shot before 3rd trimester to prevent immunization of bleeds

Identify the approximate number of cases in the U.S. and in the world, and discuss the rate of change in incidence.

~35 million world wide living with AIDS -In the USA, the CDC counted 1,160,000 cumulative cases of AIDS by the end of 2012, of whom about 800,000 had died. -In the U.S. generally incidence is decreasing while prevalence increases

What is the difference between a precipitation rxn and an agglutination rxn? Just as a reminder :)

• Major difference between precipitation and agglutination is the size of antigens involved. • Antigens are soluble (smaller) in case of precipitation while they are insoluble (larger) in agglutination • Agglutination is more sensitive than precipitation.