9.2 Fill-in-the-Blanks: T and B cells are distributed to the secondary lymphoid organs through the blood. These are then directed to their respective compartments as instructed by chemokines. For example, CCL21 is secreted by _________ of the T-cell zone in the spleen and displayed by the _______in the lymph nodes. signaling of this chemokine as well as _______through CCr7 directs the T cells into the respective T-cell zone. In contrast, _______ is the ligand for CXCr5, which is secreted by __________ and attracts B cells to the ______. T cells can also respond to CXCL13 as a subset of T cells expresses _______, which allows them to enter the B-cell follicle and participate in the formation of the germinal center.
9.3 Multiple Choice: Which of the following correctly describes events necessary for naive T-cell entry into the lymph node?
A. CCr7 signaling induces Gαi, which results in lowered affinity for integrin binding.
B. upregulation of s1p receptor on naive T cells promotes migration into the lymph node.
C. rolling in the hev exposes the T cell to CCL21, which activates LFa-1 and promotes migration.
D. MadCaM-1 expression on the hev interacts with Cd62L on the T cell and promotes migration into the lymph node.
9.4 Short Answer: In some cases, hsv or influenza viruses infect antigen-presenting cells from peripheral tissues that do not present the viral antigens to naive T cells. how is the immune system able to develop an adaptive immune response to such pathogens?
9.5 True or False: TLr stimulation induces CCr7 expression in the dendritic cells, which promotes migration to the lymph node through the bloodstream.
9.6 Matching: Classify each of the following activation signatures as a conventional dendritic cell (cdC) or plasmacytoid dendritic cell (pdC) pathogen response.
___1. production of CCL18 ___2. Continuous MhC recycling upon activation ___3. expression of dC-sIGn ___4. expression of Cd80 and Cd86 ___5. Cd40L expression upon TLr-9 stimulation 9.7 Short Answer: how does the process of antigen presentation differ among B cells, dendritic cells, and macrophages in the context of an immune response?
9.8 Multiple Choice: Which of the following is a common consequence of TCr and CCr7 signaling?
A. Integrin activation
B. positive selection C. Th1 induction D. Th2 induction 9.9 Multiple Choice: Which of the following describes a mechanism by which Cd28 signaling can increase IL-2 production?
A. Cd28 signaling induces the expression of proteins that stabilize the IL-2 mrna sequence.
B. pI 3-kinase inhibits akt, supporting IL-2 production by cell cycle arrest.
C. pI 3-kinase suppresses the production of ap-1 and nFκB, thereby increasing IL-2 production.
9.10 True or False: In the majority of viral infections, Cd8 T-cell activation requires Cd4 T-cell help.
9.11 Matching: Match each Cd4 T cell subset-specific secreted cytokine with its respective effector function.
A. IL-17 i. eradication of intracellular infections
B. IL-4 ii. response to extracellular bacteria
C. IFn-γ iii. Control of extracellular parasites
D. IL-10 iv. suppression of T-cell responses 9.12 Matching: The following cytokines drive Cd4 Th subset effector differentiation. Match each with its respective subset-specific transcription factor.
A. IFn-γ i. rorγt B. IL-4 ii. Foxp3
C. IL-6 and TGF-β iii. T-bet