Exam 2 Blue Version

Fall 2009 BLUE VERSION Exam II MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question. 1) If a double positive T cell does not bind to MHC/peptide, it will avoid apoptosis. 1) A) True B) False 2) What gene segments encode the variable region of m (mu) chain? 2) A) V, D, J, and C gene segments B) V, D, and J gene segments C) V, J, and C gene segments D) V and J gene segments 3) The genes that encode polymorphic MHC II molecules are HLA-DP, HLA-DM, and HLA-DQ. 3) A) True B) False 4) What is the difference between immature and mature dendritic cells? 4) A) immature dendritic cells have more TLRs on the surface than mature dendritic cells B) immature dendritic cells have more B7-1 and B7-2 (CD80/CD86) on the surface than mature dendritic cells C) immature dendritic cells have more MHC molecules on the surface than mature dendritic cells D) mature dendritic cells have more CD40 ligand on the surface than immature dendritic cells 5) The RSS sequences encode the most variable region of antibodies and TCRs. 5) A) True B) False 6) A patient's haplotype includes the following gene: HLA-B 12 34 . What do we know about that 6) gene? A) the gene encodes the beta chain of a MHC II molecule B) the gene can be detected by PCR primers in group 34 C) the gene encodes the beta chain of a MHC I molecule D) more than one of the above are correct 7) How do antigen presenting cells activate naive helper T cells? 7) A) the naive T cell is primed by a cytotoxic T cell then a dendritic cell helps it differentiate B) the naive T cell is primed by a dendritic cell and then a B cell helps it differentiate C) the naive T cell is primed by a B cell then a dendritic cell helps it differentiate D) the naive T cell is primed by a neutrophil then a dendritic cell helps it differentiate 8) How could a virus stop the helper T cell response? 8) A) inhibit production of cathepsin B) inhibit production of the chaperone calnexin C) inhibit production of TAP D) more than one of the above would protect against helper T cells 9) What gene rearrangement occurs in pre-T cells? 9) A) Va rearranges to DaJa B) Va rearranges to Ja C) Vb rearranges to DbJb D) Vb rearranges to Jb 1 10) Calreticulin is a chaperone that stabilized the entire MHC I molecule, versus other chaperones that stabilize just one of the polypeptides within a MHC I molecule. A) True B) False 10) 11) If you perform a cytotoxicity assay to find an immunodominant epitope, the sample that has the most radioactivity in the cells and the least radioactivity in the supernatant contains the cells with the immunodominant epitope. A) True B) False 12) The TCR lacks an ITAM in its cytoplasmic tail but CD3 has an ITAM and is able to activate signaling in a T cell after CD3 binds to its ligand on the antigen presenting cell. A) True B) False 11) 12) 13) What type of MHC molecule is able to present small peptides (ex: 7 amino acids long)? 13) A) the same MHC molecule that is used to activate helper T cells B) the same MHC molecule that is stabilized by invariant chain C) the same MHC molecule that contains b2m (beta 2 microglobulin) D) more than one of the above is correct. 14) Iga and Igb have a similar function as z (zeta) chain. 14) A) True B) False 15) Pentameric IgM usually has a higher avidity for a monovalent antigen than monomeric IgG. 15) A) True B) False 16) A signal joint forms when RAG links the "12 spacer" in a RSS sequence directly to a "23 spacer" in another RSS sequence A) True B) False 17) Malaria is caused by infection with a parasite and is a difficult disease for the immune system to respond to because: A) the parasite lacks MHC II B) the parasite lacks MHC I C) the parasite infects red blood cells D) the parasite has no protein antigens 18) If you wanted to use a FACS machine to sort out natural regulatory T cells from a thymus, you would want the machine to isolate the CD4+ CD25+ cells. A) True B) False 16) 17) 18) 19) Why do scientists use HAT media while making hydridomas? 19) A) unfused plasma cells can not synthesize DNA while growing in HAT media B) unfusued mutant myeloma cells can not secrete antibodies while growing in HAT media C) unfused mutant myeloma cells can not synthesize DNA while growing in HAT media D) unfused plasma cells can not secrete antibodies while growing in HAT media 2 20) How could you stop the co-expression of IgM and IgD on the surface of a B cell? 20) A) by inhibiting Tdt activity B) by inhibiting RAG in immature B cells C) by removing the k chain genes from the genome D) by inhibiting RNA splicing enzymes 21) b2 microglobulin helps to stabilize the alpha chain of the MHC molecule and also binds to CD8 on the T cell. A) True B) False 21) 22) Which of the following characteristics applies to small immune complexes? 22) A) small immune complexes are more common in patients with chronic infections than large immune complexes B) small immune complexes are less likely to deposit in capillaries than large immune complexes C) small immune complexes are more easily phagocytosed than large immune complexes D) more than one of the above is correct 23) Pro-T cells can skip the other developmental stages and differentiate directly into mature gd T cells 23) A) True B) False 24) If a mouse lacked Artemis, what would you expect to observe in the mouse? 24) A) a decreased number of MHC II molecules B) a decreased number of CD34+ cells C) a decreased number of MHC I molecules D) a decreased number of CD19+ cells 25) To increase the affinity between a peptide and the TCR, one could: 25) A) change the non-anchor residues B) change the beta-pleated sheets of the peptide binding motif C) change the anchor residues D) two of the above are correct 26) What is the difference between N and P nucleotides? 26) A) only one (either N or P nucleotides) are added during VDJ rearrangement B) only one (either N or P nucleotides) are added during C gene rearrangement C) only one (either N or P nucleotides) are added to DNA in pre-T cells D) only one (either N or P nucleotides) are added by RAG 27) The b1 region of MHC II binds to the TCR on CD4+ T cells but the b1 region does not bind to CD4. 27) A) True B) False 28) Finding a donor for a transplant is difficult because a donor's cells may only express the maternal alleles of the MHC genes while the recipient's cells may only express the paternal alleles of the MHC genes. A) True B) False 28) 29) Because of allelic exclusion, only one allele of the HLA-A, HLA-B, and HLA-B genes is expressed in a cell. A) True B) False 3 29) 30) Peptides produced in the lysosome bind to MHC when CLIP is removed. 30) A) True B) False 31) The pre-Ta gene is produced without gene rearrangement and must be expressed in order for a T cell to differentiate to the "double positive" stage. A) True B) False 32) When immature T cells bind to self peptide with high affinity, they die. When immature T cells bind to foreign peptide with high affinity, they live. A) True B) False 33) Because of allelic exclusion, the allele for the d heavy chain can not be expressed in immature B cells. A) True B) False 31) 32) 33) 34) Something that MHC I and MHC II have in common is: 34) A) MHC I and MHC II each have two polypeptide chains that bind to the peptide being presented B) both types of genes (MHC I and MHC II) are transcribed following gene rearrangement C) both MHC I and MHC II are stabilized on the surface by CD3 D) both MHC I and MHC II need to peptides in order to be transported to the surface of a cell 35) In the absence of AIRE, thymic epithelial cells would be unable to present central nervous system peptides. A) True B) False 35) 36) CD43+ B cells are located near the outer edge of the bone marrow that touches the hard bone. 36) A) True B) False 37) The difference between CD5+ B cells and follicular B cells is: 37) A) CD5+ B cells are found in the spleen and follicular B cells are found in all secondary lympoid organs B) follicular B cells need antigen to be activated whereas CD5+ B cells do not need antigen to be activated C) CD5+ B cells only activate gd T cells whereas follicular B cells activate both gd and ab T cells D) when first activated, follicular B cells secrete IgM whereas CD5+ B cells secrete IgD 38) What is the difference between "double positive" and "double negative" cells in the thymus? 38) A) only one (either "double positive" or "double negative" responds to chemokines produced by thymic epithelial cells B) only one (either "double positive" or "double negative" have the a chain polypeptide C) only one (either "double positive" or "double negative" are found in the cortex of the thymus D) only one (either "double positive" or "double negative" expresses l5 39) gd T cell receptors do not bind to MHC I or MHC II. 39) A) True B) False 40) T cell activation is regulated when SLAM on the T cell binds to SLAM on antigen presenting cells. 40) A) True B) False 4 41) If you were performing an ELISA to determine whether a patient had gp120, a HIV protein, in their blood, what would be the first step of the ELISA? A) attaching anti-IgG to the well B) attaching anti-gp120 to the well C) attaching enzyme linked anti-gp120 to the well D) attaching gp120 to the well 41) 42) What is the difference between the professional antigen presenting cells (APC)? 42) A) only one type of professional APC constituively expresses CD80 and CD86 (B7-1/B7-2) B) only one type of professional APC is located in the spleen whereas all of the professional APCs are located in the lymph nodes C) only one type of professional APC has the molecules needed to activate cytotoxic T cells D) the level of MHC only varies on one type of professional APC, the other types of professional APCs never change the amount of MHC on their surface. 43) The difference between TCRs and antibodies is: 43) A) only one (either TCRs or antibodies) is able to recruit kinases to its cytoplasmic tail B) only one (either TCRs or antibodies) is found in a membrane-bound form C) only one (either TCRs or antibodies) contains CDRs that bind to antigens D) only one (either TCRs or antibodies) binds to lipid antigens 44) Since k (kappa) gene segments are rearranged before l (lambda) gene segments, more B cells express chain. A) True B) False 44) 45) TAP is needed to guide peptides to the same MHC molecules that are stabilized by invariant chain. 45) A) True B) False 46) EXTRA CREDIT: People with Bare Lymphocyte Syndrome lack: 46) A) MHC II B) IgM C) MHC I D) AIRE 5