Before beginning the practice test, please read this announcement:

Transcription

1 Before beginning the practice test, please read this announcement: As mentioned in the UCF SI Wordpress site and in class, I will not be able to hold a review session for this test due to my personal schedule. I do encourage you to use this practice test to check where you are as far as knowing the material, and I encourage you to put in the effort to try and find where in the PowerPoints the answers are (I can assure you that ALL the questions can be answered with the lecture s PPTs). I also recommend you to come to my SI Sessions this week whether you have any specific questions, or if you just want to go over a certain concept or topic the more the merrier! The practice test begins in the next page.

2 Practice Test Test 4 1) T cell precursors migrate from the bone marrow to the thymus through the lymph canals, and enter the thymus through the afferent lymphatic... 2) DiGeorge s Syndrome: a. Involves a deletion in chromosome 22. b. The thymus is not affected at all. c. Affected person is susceptible to a wide range of opportunistic infections, and resembles SCID.. e. A & C. 3) Which of the following statement/statements is/are true about the thymus? a. A thymectomy in an adult will not affect T cell immunity in an adult. b. The thymus is most active in older people. c. Because the thymus involves as we grow older, as time passes we gradually have a lower T cell count in our body. 4) Which of the following surface proteins will an uncommitted progenitor cell that just entered the thymus have? a. CD4 b. CD8 c. CD34 d. IL-7 receptor e. C & D 5) A double negative progenitor T cell: a. Is will never be a double positive Thymocyte b. Does not have CD4 and CD8 on its surface, and does have CD2 and CD5. c. Needs IL-7 and Notch 1 to receive the signals that drive their maturation. d. B & C. 6) Rearrangement of the β chain occurs before rearrangement of the γ/δ genes. 7) The Membrane Attack Complex is formed by: a. C3b 2Bb b. ic3b c. C4b2a3b e. None of the above

3 8) Which of the following is NOT a signal that originates from a successful rearrangement of a β chain and the pre T cell receptor? a. Stimulates proliferation b. Stimulates expression of either CD4 or CD8 co-receptors. c. Stops any additional TCR β chain locus rearrangement. d. Signals to become permissive for α chain rearrangenemet. 9) Once the first chain of the β chain of the TCR is rearranged (it s also successfully tested with by forming the pre-tcr), and the cell has finished proliferating: a. The RAG genes are turned back on. b. Rearrangement of the α chain locus is induced. c. There is a bigger chance that the rearranging thymocyte will become a γ: δ T cell than a α: β T cell. e. All of the above. 10) The pre T cell receptor is composed of a. Fully formed TCR (with both α and β chains). b. β chain and a pretα. c. CD3 and ζ chains. e. B & C 11) How many tries, per chromosome, does a T cell have to produce a functioning β chain? a. 1 b. 2 c. 4 d. x 2 1 = 24 e. π 12) The α chain locus has only one chance of rearrangement per chromosome.. 13) The second checkpoint in T cell development: a. Makes sure that the surrogate α chain can bind to the β chain. b. Makes sure that the α chain can bind to the β chain. c. Tests whether the newly formed TCR can bind to self-antigens. d. All the above 14) Both types of T cells (α: β and γ: δ) have to go through positive selection before leaving the thymus. 15) If Prof Weigel is heterozygous for his HLA genes, how many different HLA can he produce? a. 12 b. 3 c. 6

4 16) Which of the following statement/statements is/are true about positive selection? a. Takes place in the medulla of the thymus b. Is mediated by cortical epithelial cells that have self MHC I or MHC II loaded with exogenous peptides. c. Will determine whether the double positive T cell becomes a CD4 T cell or a CD 8 T cell (single positive). d. A thymocyte will die after 30 days if it does not receive a positive signal from the cortical epithelial cell. e. B & C. 17) Rearrangement of the α chain locus continues throughout the process of positive selection, and stops whenever the T cell is positively selected 18) Which of the following statement is/are true about negative selection? a. Is mediated only by cortical epithelial cells b. This process occurs in the cortex of the thymus c. Stromal cells are involved, which are the cells that carry MHC loaded with self-peptides. d. T cells that bind too strongly to a self-peptide die by apoptosis. e. All of the above. 19) A T regulatory cell: a. Is a type of CD4 T cell. b. Expresses CD25, which is the transcriptional repressor used by T Regulatory Cells, and is unique to these cells. c. Expresses FoxP3, which is the transcriptional repressor used by T Regulatory Cells, and is unique to these cells. 20) Positive selection tests whether the and regions of the TCR can bind to a/an. a. CDR 3; CDR 2; Self Antigen b. CDR 3; CDR 1; MHC c. CDR 1; CDR 2; MHC d. CDR 1; CDR 2; Self Antigen e. CDR 3; CDR 2; MHC. 21) Which of the following statements regarding dendritic cells is/are not true a. When immature, the dendritic cell is located in a tissue and is performing endocytosis/phagocytosis. b. A mature dendritic cell is called a Langerhan cell c. DEC 205 is a protein involved in receptor mediated endocytosis. d. Micropinocytosis is the process in which the dendritic cell engulfs extracellular fluid. e. B & D

5 22) Circulating naïve T cells will: a. Enter the thymus though HEV thanks to the CCL 19 and CCL 21 gradient. b. Enter the secondary lymphoid tissue though HEV thanks to the CCL 19 and CCL 21 gradient. c. Will not be able to pass through the HEV if CCR 7 is not present on the T cell surface. d. B & C e. A & C 23) When the T cell is screening the peptide:mhc complexes on an APC, and recognizes the peptide: a. The T cell s LFA-1 binds to ICAM-1 or ICAM-2 on the APC. b. ICAM-3 on the dendritic cell binds on DC-SIGN on an activated t cell. c. SP1 receptors will be suppressed if the T cell is able to bind successfully to a peptide:mhc complex. 24) Clonal expansion refers to the moment where the T cell recognizes the MHC:peptided complex on the dendritic cell 25) Which of the following statement/s regarding the costimulatory protein B7 is/are true? a. CTLA-4 has a twenty-fold binding strength less than CD28. b. B7 (on the surface of the T cell) binds to CD28 (on the surface of the P-APC), and is the signal that indicates whether the peptide loaded on the MHC II is exogenous. c. When CTLA-4 binds to B7, the T cell proliferation slows down. e. All of the above 26) You are a PhD student testing the hypothesis that dendritic cells express B7 on their surface only when the antigen loaded on the MHC II is of an infectious (exogenous) nature. To test this, you load a few Langerhan cells with an exogenous peptide, let it develop into mature dendritic cells, and you insert them into secondary lymphoid tissues of one of your lab rats. A few hours later you take a histologic sample of those lymph node and set them up to be analyzed by fluorescence microscopy. You realize that you ran out of the fluorescent stain specific for B7 and you need to figure out a way to check for the presence of B7 on these dendritic cells. Assuming that the exogenous peptide was recognized by the T cells, which surface proteins on the T cell would you stain that will confirm the presence of B7 expression of the dendritic cell? a. DC-SIGN b. MHC II c. CTLA 4 d. CD 28 e. C & D 27) Professional Antigen Presenting Cells are: a. B Cells b. Macrophages c. Dendritic Cells d. B & C e. All of the Above

6 28) Which of the following is the correct outcome for the signaling pathways initiated by the T-cell receptor complex, its CD4 co-receptor and CD28? a. Production of IL-2 that will stimulate cell division through exocrine signaling. b. Production of IL-2 that will stimulate cell division through autocrine signaling. c. Production of IL-7 that will stimulate cell division through exocrine signaling d. Production of IL-7 that will stimulate cell division through endocrine signaling. 29) The high affinity IL-2 receptor is composed by: a. α and ß chains. b. α, ß and γ chains. c. γ and ß chains. 30) A T cell that recognizes a self-antigen will most likely: a. Activate and proliferate. b. Will be rendered anergic because of the lack of B7 on the P-APC. c. Will be rendered anergic because of the presence of B7 on the P-APC.. 31) All leukocytes are lymphocytes 32) Which of the following is not a cell that can differentiate from a CD4 T cell? a. Th1 b. Th2 c. Th17 d. T Cytotoxic e. All of these cells differentiate from CD4 T cells. 33) IL-4 will induce differentiation to which type of T cell? a. Th1 b. Th2 c. Th17 d. Tfh e. Treg 34) Which of the following cells is mismatched with its function? a. Th1: reduces inflammation at the site of infection b. Th2: defense against pararsites c. Th17: recruits macrophages at the site of infection d. Tfh: help naïve B cells in germinal center to become plasma cells or memory cells. e. A & C 35) The disease Lepromatous leprosy: a. Is a low infectivity disease that causes differentiation and a bias for Th1 cells. b. Is a high infectivity disease that causes differentiation and a bias for Th2 cells. c. Will have a higher concentration of IL-4, IL-5 and IL-10. e. B & C

7 36) CD4 T cells can induce activation of CD8 T cells through endocrine secretion of IL-2. 37) An activated CD4 T cell will have on its surface: a. L selectin b. VLA-4 c. LFA-1 e. B & C 38) An effector CD8 T still needs B7 to be able to respond to its specific antigen 39) Which of the following statement/s is/are true regarding cytokine receptors? a. They have a cytoplasmic tail that are associated with JAK proteins. b. STATs activate JAKs, which in turn will migrate to the nucleus and activate specific genes. c. JAKs activate STATs, which in turn will migrate to the nucleus and activate specific genes. e. A & C 40) T Cytotoxic Cells cause necrosis of cells that are infected with a viral pathogen. 41) INF γ plays an important role in fighting viral infections because: a. It increases the presentation of peptides on MHC I. b. It activates macrophages that will help with disposing of dead cells. c. Inhibits the replication of viruses in the infected cells e. All the above 42) The signal/signals that a macrophage needs to be activated from a T cell is/are? a. Primary signal: CD40 ligand/cd40 receptor Secondary: IFN-γ b. Primary signal: IFN-γ Secondary: CD40 ligand/cd40 receptor c. Primary signal: IFN-γ d. Primary signal: CD40 ligand/cd40 receptor 43) A pathogen that invades the intracellular vesicular system of cells: a. Reduce the response of Th1 cells. b. Cannot be reached by antibodies, but its peptides can be presented on MHC I molecules that will activate CD8 T cells c. Will not affect the ability of macrophages to lyse bacteria once in its phagolysosome. 44) Cognate interaction refers to the ability of a B cell to recognize the same antigen as the T cell.

8 45) Which lymphocyte is specialized in fighting parasitic infections, and has orange staining when looked in the microscope? a. Neutrophil b. Eosinophil c. Basophil d. Macrophage For questions match the T cell with the correct cytokine/cytotoxin that they secrete 46) Cytotoxic T cell a. TGF-ß 47) Th1 b. IL-17 48) Th2 c. Perforin, Granulysin, IL-2, INF-γ 49) T-reg d. IL-4, IL-5 50) Th17 e. INF-γ, GM-CSF, TNFα, IL-2. Extra Questions: 1. Giulia McGettigan was born full term with malformed jaw, cleft palate, ventricular septal defect, and hypocalcemia. Within 48 hours of birth she developed muscle tetany, convulsions, tachypnea, and a systolic murmur. A chest X-ray showed an enlarged heart and the absence of a thymic shadow. Blood test showed a severely low CD4 and CD8 T cell count, but B cell count was within normal limits. Fluorescence in situ hybridization of the buccal mucosa revealed a small deletion in the lon arm of chromosome 22. Giulia failed to thrive and battled chronic diarrhea and opportunistic infections, including oral candidiasis that eventually lead to her death. a. What is the most likely cause of her immunodeficiency? i. Make sure you give a detailed answer that explains the reason of her symptoms. 2. Clyclosporin A is an immunosuppressant drug commonly used in transplant patients to prevent graft rejection by alloreactive T cells (alloreactive = reactive towards the transplanted graft). It acts by interfering with the signaling pathway that leads from the T cell receptor to transcription in the nucleus of the genes for cytokine IL-2 and α-chain of the IL-2 receptor. a. Why preventing transcription of these genes lead to immunosuppression? 3. Vijay Kumar, a 19-year-old male who had emigrated to the US from South India two years before, developed lesions in his nasal mucosa, and nodular skin lesions on his cheeks and buttocks. Examination of a stained biopsy of a skin lesion revealed numerous clumps of mycobacteria. Further analysis of the sample revealed a high concentration of IL-4, IL-5 and IL- 10. a. What is the most likely diagnosis? b. Explain the mechanisms behind the disease. Please read important info in the next page!!!!

9 The Extra Questions are there to spark your synapsis and make you think a little; use them to test your understanding. Keep in mind that I will not be posting the answer for these extra questions NOTE: Although I am posting the answer key for this practice exam, I want you to use this practice to gauge your knowledge, and try to figure out the right answer by yourself before looking in the answer key. Additionally, I cannot guarantee that these answers are correct, and I cannot guarantee that these questions will be in the exam, as I am not a TA for the class and I do see the actual tests at all. Good Luck!!