IMMUNO CH. 11 Revised .

IMMUNO CH. 11 Revised .1. What event initiates an adaptive immune response? A. The interaction of a B cell with a TH cell B. The expression of cytokines CD4 or CD8 C. The production of MHC class I or II molecules D. The interaction of a naïve T cell with an antigen-presenting cell E. The phagocytosis of a pathogen by a macrophage answer- D 3. CD4+ T cells recognize: A. CD8+ markers. B. IgM. C. MHC class I peptides. D. MHC class II peptides. E. both MHC class I and class II peptides. answer- D 5. CD4+ T cells become helper T cells in response to: A. exposure to antigen. B. exposure to MHC class II peptide. C. exposure to any MHC peptide. D. exposure to MZ B cells. E. exposure to TNF-a. answer- B 8. Bonds formed between the T cell and a dendritic cell are relatively weak. Which of the following help to strengthen this association so that a T cell can see which antigen is being presented by a dendritic cell? A. CD28/LFA-5 B. CD 28 C. ICAM-1/LFA-1 D. IL-2R E. Pattern-recognition molecules answer- C 9. Which of the following is required for T-cell activation? A. Antigen-specific TCR binding to MHC peptide B. Expression of CD4+ or CD8+ C. Interaction with CD80, CD86, or ICOS-L D. Both A and B E. Both A and C answer- E 10. Co-receptor molecules are required by TC and TH cells so that the TCR can stably bind to the MHC peptide presenting the antigen. Which co-receptor molecules are common to both TC and TH cells and their respective antigen presenting cells? A. CD2/LFA-3 B. CD28/B7 C. CD45R/CD22 D. LFA-1/ICAM-1 E. All but B answer- E 11. CTLA-4 is a co-stimulatory receptor on T cells that belongs to the same family as the CD28 co-stimulatory receptor. However, CTLA-4 is antagonistic to CD28. Which of the following could be a functional advantage of CTLA-4 expression within the immune response? A. CTLA-4 competes with CD28 for ligand binding so that, if CD28 binds to its ligand, the response will be magnified. B. CTLA-4 is often given to immunosuppressed individuals to trigger an immune response. C. CTLA-4 limits the immune response of TC and TH cells after an infection has been cleared. D. CTLA-4 limits TC activity in healthy individuals during a viral infection. E. CTLA-4 reduces the lag time between antigen presentation to a TH cell and B cell activation. answer- C 12. PD-1 is a negative co-stimulatory signal expressed by tumor cells. What advantage would the expression of PD-1 have in a tumor cell avoiding the immune response? A. None. Tumor cells are recognized as self and therefore do not pose a health threat. B. Tumor cells can avoid being killed by activated TC cells. C. Tumor cells can avoid apoptosis triggered by TH cells. D. Tumor cells avoid phagocytosis by den