1. Purified naive T cells isolated from a T-cell receptor transgenic mouse repre
ID: 204118 • Letter: 1
Question
1. Purified naive T cells isolated from a T-cell receptor transgenic mouse represent a homogeneous population of cells with specificity for a single known peptide:MHC complex. This specific peptide:MHC complex can be purified and formed into multivalent complexes, such as peptide:MHC tetramers. When the naive T cells are stimulated with their ‘antigen’ in the form of these peptide:MHC tetramers, the T cells show activation responses, including the up-regulation of genes that are induced within several hours after T-cell receptor stimulation. However, these activated T cells fail to undergo robust proliferation, and the majority of cells die after 3–4 days in culture. T cell proliferation and survival could be greatly augmented by addition of:
A. Anti-inflammatory cytokines
B. Toll-like receptor ligands
C. Antibodies to the T-cell receptor
D. B7 ligands for CD28
E. The integrin LFA-1
2. Inbred strains of mice often generate highly polarized CD4 T cell responses to specific infections that are dominated by one subset of effector cells. In the case of Balb/c mice infected with the intracellular protozoan Leishmania major, a robust CD4 T cell response is elicited, generating large numbers of L. major-specific T cells; however, this response does not eliminate the pathogen, and instead the mice succumb to the infection. One likely explanation for this finding is:
A. L. major produces immune evasion molecules that prevent pathogen clearance.
B. The antibody response to L. major is too weak to eradicate the pathogen.
C. The CD4 T cell response produces effector cytokines that do not activate macrophages.
D. The CD4 T cells have differentiated into TH1 instead of TH2 effector cells.
E. The TFH cells specific for L. major induce a non-protective class of immunoglobulins.
3. True/False: In a lymph node, nTreg cells are able to inhibit the responses of other T cells in their vicinity. This inhibition is specific, as the nTreg cell and the naive T cell must share the same antigen specificity.
4. Eosinophils are a subset of granulocytes that normally reside in the circulation. When activated, these cells secrete toxic compounds that are a key component in the eradication of helminthic parasite infections. Eosinophils are recruited to sites of parasite infections by:
A. Interferon-gamma produced by TH1 cells
B. CCL11 produced by TH2 cells
C.Interferon-gamma produced by CD8 cytotoxic T cells
D.CCL20 produced by TH17 cells
E. GM-CSF produced by TH1, TH2, and TH17 cells
Explanation / Answer
1.a. anti inflammatory cytokines.
Because anti inflammatory cytokines like IL-2 may increase the rate proliferation when exposed with antigens.
2. C. the CD4 T cell differentiated into TH1 instead of TH2 efector cells
3. True.
Regulatory T cells are T suppressor cells which prevents autoimmune disease by maintaining tolerance to self antigen. Which helps our body from self destruction from native T cells.
4 E. GM-CSF produced by TH1, TH2 and TH17 cells.
During the stage of parasitic infection, at the site of infection, the eosinophill level is increased under the influence of TH 2 derived GM- CSF
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