Immunology & Serology Final Exam Complete Questions And Answers Well Elaborated.

a. it occurs in primary lymphoid organs - correct answer all of the following are true in reference to T-cell priming except _________. a. it occurs in primary lymphoid organs b. It transforms naïve T cells into differentiated effector T cells c. It is the first stage of a primary adaptive immune response d. It requires interaction between naïve T cells and antigen-presenting cells e. It takes place in many locations including, but not limited to, lymph nodes, Peyer's patched, and the tonsils b. macrophages resident in infected tissues, e. immature dendritic cells - correct answer Which of the following cell types is unable to interact with naïve T cells and induce their activation? (Select all that apply.) a. B cells b. Macrophages resident in infected tissues c. Macrophages resident in secondary lymphoid tissue d. Interdigitating reticular cells e. Immature dendritic cells e. expression of toll-like receptor TLR9 - correct answer When an immature dendritic cell becomes an activated dendritic cell, all of the following changes occur except _____. a. Confinement to T-cell regions of lymph node cortex b. Development of elaborate finger-like processes c. Upregulated expression of MHC class II at the cell surface d. Loss of antigen-processing functions e. Expression of Toll-like receptor TLR9 d. Naïve T cells occupy both the cortex and the medulla of the lymph nodes. - correct answer Identify which of the following statements regarding naïve T cells is incorrect. a. Naïve T cells enter lymph node in two different ways, from the blood or from the lymph. b. Naïve T cells can only be activated in secondary lymphoid tissues. c. Naïve T cells differentiate into effector T cells after T-cell priming has occurred. d. Naïve T cells occupy both the cortex and the medulla of the lymph nodes. e. Naïve T cells are only activated by dendritic cells, not by macrophages or B cells. a. VLA-4 - correct answer Homing of effector T cells to inflamed tissue facilitated by the upregulation of _____ on the surface of the effector T cell. a. VLA-4 b. L-selectin c. CD28 d. VCAM-1 e. B7 e. Naïve T cells express high levels of S1P receptors on their surface. - correct answer Identify which of the following statements regarding naïve T cells is incorrect. a. Naïve T cells have the capacity to survive for many years as nondividing circulating cells in the absence of a specific antigen. b. Naïve T cells express LFA-1 molecules that change their conformation after encountering a specific peptide:MHC complex. c. Naïve T cells exit from the lymph nodes using the same route as effector T cells. d. Naïve T cells express ICAM-3, which binds to DC-SIGN on dendritic cells with high affinity. e. Naïve T cells express high levels of S1P receptors on their surface. d. They cease to secrete and respond to interleukin-2 (IL-2). - correct answer Which of the following statements regarding T cells activated by specific antigen is incorrect? a. They receive co-stimulatory signals through CD28 b. They suppress expression of sphingosine 1-phosphate (S1P). c. They take several days before differentiating into effector T cells. d. They cease to secrete and respond to interleukin-2 (IL-2). e. They begin to express CTLA-4, which serves to limit T-cell proliferation. b. Dendritic cells upregulate B7 after engaging innate immunity receptors at site of infection. - correct answer Which of the following explains why dendritic cells, but not macrophages or B cells, contribute to the activation of naïve T cells? a. Macrophages and B cells do not express MHC class II molecules until they are activated. b. Dendritic cells upregulate B7 after engaging innate immunity receptors at site of infection. c. Dendritic cells express higher levels of CTLA4. d. Macrophages and B cells do not process antigen. e. Dendritic cells use Toll-like receptors to hold antigen in place for extended periods of time. d. 100 times the number of - correct answer If CD4 or CD8 co-receptors are absent, they approximately _____ specific peptide:MHC complexes are needed to activate a T cell. a. Twice the number of b. 10 times the number of c. 20 times the number of d. 100 times the number of e. 1000 times the number o c. T-cell anergy - correct answer Antigen recognition by T cells in the absence of co-stimulation results in a. Upregulation of B7 b. Expression of the high-affinity IL-2 receptor c. T-cell anergy d. T-cell apoptosis e. Phosphorylation of immunoreceptor tyrosine-based activation motifs. b. CD4 TFH cells - correct answer _____ cells remain in, rather than leave, the secondary lymphoid organs in which they differentiated. a. CD4 TH1 cells b. CD4 TFH cells c. CD8 cytotoxic T cells d. Regulatory CD4 T cells e. All of the above T reg cells - correct answer suppress effector CD4 and CD8 T-cell function CD8 T cells - correct answer induce apoptosis of target cells after targeted delivery of cytotoxins CD4 Th1 cells - correct answer differentiate under the influence of IL-12 and IFN-gamma CD4 Th2 cells - correct answer help basophils, mast cells, eosinophils, and B cells respond to parasitic infections CD4 Th17 cells - correct answer facilitate neutrophil response to fungal and extracellular bacterial infections b. Cooperation between T follicular helper (TFH) and naïve B cells bearing specificity for different epitopes of the same antigen and where the B cell serves as the antigen presenting cell - correct answer Linked recognition is best described as _____. a. The delivery of the co-stimulatory signal by antigen-presenting cells to T cells b. Cooperation between T follicular helper (TFH) and naïve B cells bearing specificity for different epitopes of the same antigen and where the B cell serves as the antigen presenting cell c. Linking Toll-like receptors and the innate immune response d. The interaction between processed antigenic peptides and MHC molecules during antigen presentation e. The region of contact between T cells and antigen-presenting cells involving cell-adhesion molecules and other cell-surface receptor-ligand pairs b. lepromatous leprosy - correct answer a 19-year-old male emigrated to the US and two years before he developed lesions in his nasal mucosa and nodular skin lesions on his cheeks and buttocks. examination of a stained biopsy skin lesion revealed a number of clumps of mycobacteria. T cells in the lesions were secreting IL-4, IL-5, and IL-10. What is his likely diagnosis? a. close association with complement receptor 1 (CR1), CD19, and CD81 - correct answer All of the following are associated with B-cell activation except _____. a. close association with complement receptor 1 (CR1), CD19, and CD81 b. clustering of surface immunoglobulin c. activation of cytoplasmic protein tyrosine kinases d. participation of cytoplasmic tails of Igα and Igβ