Academic Integrity: tutoring, explanations, and feedback — we don’t complete graded work or submit on a student’s behalf.

1. Each subset of effector T cells produces a distinct array of secreted factors

ID: 204123 • Letter: 1

Question

1. Each subset of effector T cells produces a distinct array of secreted factors known as cytokines. One common feature of nearly all effector T cell responses is the rapid production of increased numbers of macrophages, granulocytes, and dendritic cells from the bone marrow. This response occurs due to:
A. Effector T cell trafficking to the bone marrow to activate hematopoietic progenitor cells
B. Depletion of peripheral myeloid cells after leaving the blood, leading to increased bone marrow production
C.Inflammation-induced blood vessel dilation causing transient reductions in circulating myeloid cells
D. Pathogen-induced migration of tissue-resident dendritic cells to lymph nodes inducing new dendritic cell production
E. Effector T cell production of GM-CSF that traffics to the bone marrow

2. A mouse is immunized with a single 9 amino acid peptide derived from the influenza virus. This peptide binds to MHC class I and produces an epitope (peptide:MHC complex) recognized by a small number of naive CD8 T cells in the mouse. The peptide is mixed with CpG oligonucleotides that are ligands for TLR-9. Surprisingly, this immunization regimen generates a very poor cytotoxic CD8 effector response to targets coated with this peptide compared to immunization with a preparation of intact heat-killed influenza virus mixed with CpG oligonucleotides. The enhanced cytotoxic T cell response to the peptide observed following immunization with intact viral particles compared to the peptide alone is due to:
A. The presence of CD4 T cell epitopes in the intact virus
B. The increased production of type I interferon elicited by the intact virus
C. The presence of additional CD8 epitopes in the intact virus
D.   Presentation of peptides by macrophages instead of dendritic cells
E.   Up-regulation of MHC class I molecules by the intact virus

3. What can you do to tweak the Th1 vs Th2 response?

Explanation / Answer

Ans1. :- D. Pathogen-induced migration of tissue-resident dendritic cells to lymph nodes inducing ew dendritic cell production.