Which of the following statements about T cells is false? a. Helper T cells release cytokines while cytotoxic T cells kill the infected cell. b. Helper T cells are CD4+, while cytotoxic T cells are CD8+. c. MHC II is a receptor found on most body cells, while MHC I is a receptor found on immune cells only. d. The T cell receptor is found on both CD4+ and CD8+ T cells.

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.

How does IL-2 affect T-cells? Select all the mechanisms in T-cells that utilize IL-2. Select one or more: a. Autocrine action of IL-2 causes proliferation of T-cells. b. IL-2 secreted by CD4 T-cells activates CD8 T-cells. c. IL-2 induces the differentiation of CD4 T-cells into the TH1 subset. d. IL-2 activates dendritic cells and signals them to relocate to the lymph node. e. IL-2 signals the T-cells to remain in the lymph node after activation.

What is the function of tapasin? Select one: a. Tapasin is an antagonist of HLA-DM and causes more significant increases in MHC class I than MHC class II on the cell surface. b. Tapasin is a lectin that binds to sugar residues on MHC class I molecules, T-cell receptors, and immunoglobulins and retains them in the ER until their subunits have adopted the correct conformation. c. Tapasin is a thiol-reductase that protects the disulfide bonds of MHC class I molecules. d. Tapasin participates in peptide editing by trimming the amino terminus of peptides to ensure that the fit between peptide and MHC class II molecules is appropriate. e. Tapasin is a bridging protein that binds to both TAP and MHC class I molecules and facilitates the selection of peptides that bind tightly to MHC class I molecules.