test bank Cellular and Molecular Immunology 8th Edition Abbas Test Bank. - $15.49   Add to cart

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test bank Cellular and Molecular Immunology 8th Edition Abbas Test Bank.

test bank Cellular and Molecular Immunology 8th Edition Abbas Test Bank.. test bank Cellular and Molecular Immunology 8th Edition Abbas Test Bank. Abbas: Cellular and Molecular Immunology, 8th Edition Activation of T Lymphocytes Test Bank Multiple Choice 1. All of the following protein-protein interactions are involved in activation of naive helper T cells by antigen-presenting cells (APCs) EXCEPT binding of: A. Peptide-MHC complexes on the APC to the TCR on the T cell B. CD4 on the T cell to nonpolymorphic regions of class II MHC molecules on the APC C. Integrins on the T cell with adhesion ligands on the APC D. B7-2 on the APC with CD28 on the T cell E. CD40L on the T cell with CD40 on the APC ANS: E. CD40L is not expressed on naive T cells and is only up-regulated subsequent to activation by an antigen-presenting cell (APC). In the naive helper T cell, the TCR binds to the MHC-peptide complex whereas the CD4 coreceptor engages a conserved region on the MHC II molecule. Integrins on the T cell interact with adhesion ligands on the APC. This region of binding between the T cell and the APC is known as the immunologic synapse and also includes costimulatory interactions, such as CD28 on the T cell binding to B7 on the APC. NURSINGTB.COM 2. Which one of the following statements about MHC-TCR interactions is NOT true? A. Antigen receptors on T cells bind to MHC molecules for only brief periods of time. B. The affinity of most TCRs for peptide-MHC complexes is similar to the affinity of antibodies for their antigens. C. Only 1% or less of the MHC molecules on any antigen-presenting cell (APC) display a peptide recognized by a particular T cell. D. T cells usually require multiple engagements with an APC before a threshold of activation is reached. E. A subthreshold number of MHC-TCR interactions can lead to T cell inactivation. ANS: B. In general, the TCR binds to peptide-MHC complexes with lower affinity than antigen-antibody interactions. This relatively low-affinity interaction occurs briefly; thus, a T cell may need multiple engagements with the antigen-presenting cell (APC) before a threshold of activation occurs. If this threshold is not reached, the T cell may enter into an inactive state known as anergy. On any given APC, less than 1% of the MHC molecules display the same peptide.

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