Podcast
Questions and Answers
Which mechanism exemplifies how T regulatory cells (Tregs) limit the activation of self-reactive lymphocytes in the periphery?
Which mechanism exemplifies how T regulatory cells (Tregs) limit the activation of self-reactive lymphocytes in the periphery?
- Promoting the production of pro-inflammatory cytokines that induce apoptosis in self-reactive T cells.
- Directly activating self-reactive T cells to induce clonal expansion and subsequent anergy.
- Suppressing the growth and survival requirements of self-reactive T cells through the secretion of TGF-β. (correct)
- Enhancing the expression of co-stimulatory molecules on antigen-presenting cells to promote T cell activation.
How does the expression of CD25 on T regulatory cells (Tregs) contribute to the suppression of self-reactive T cells?
How does the expression of CD25 on T regulatory cells (Tregs) contribute to the suppression of self-reactive T cells?
- CD25 enhances the stimulatory signals received by self-reactive T cells, promoting their activation.
- CD25 depletes IL-2 from the microenvironment, limiting the access of self-reactive T cells to this essential growth factor. (correct)
- CD25 promotes the secretion of pro-inflammatory cytokines, which inhibit the function of self-reactive T cells.
- CD25 directly binds to self-antigens, preventing their interaction with T cell receptors.
What is the primary mechanism by which CTLA-4 expressed on T regulatory cells (Tregs) suppresses the activation of effector T cells?
What is the primary mechanism by which CTLA-4 expressed on T regulatory cells (Tregs) suppresses the activation of effector T cells?
- CTLA-4 enhances the secretion of IL-2, promoting effector T cell proliferation and activation.
- CTLA-4 promotes the expression of co-stimulatory molecules on APCs, enhancing T cell activation.
- CTLA-4 directly induces apoptosis in effector T cells through the activation of caspase pathways.
- CTLA-4 outcompetes CD28 for binding to B7 molecules on antigen-presenting cells (APCs), inhibiting co-stimulation. (correct)
In the context of T regulatory cell function, what is the role of the perforin-granzyme pathway?
In the context of T regulatory cell function, what is the role of the perforin-granzyme pathway?
How does IL-10 secretion by T regulatory cells suppress macrophage function?
How does IL-10 secretion by T regulatory cells suppress macrophage function?
What is the consequence of T regulatory cell infection in non-obese diabetic (NOD) mice, a model for autoimmune diabetes?
What is the consequence of T regulatory cell infection in non-obese diabetic (NOD) mice, a model for autoimmune diabetes?
Which outcome would most likely arise from a genetic defect causing a complete lack of FoxP3 expression?
Which outcome would most likely arise from a genetic defect causing a complete lack of FoxP3 expression?
A researcher is investigating novel therapeutic strategies to enhance T regulatory cell function in patients with autoimmune disease. Which of the following approaches would most likely lead to increased suppressive activity of T regulatory cells?
A researcher is investigating novel therapeutic strategies to enhance T regulatory cell function in patients with autoimmune disease. Which of the following approaches would most likely lead to increased suppressive activity of T regulatory cells?
A scientist is studying the effects of a novel drug on immune regulation. They observe that the drug increases the expression of CD80 and CD86 (B7) on antigen-presenting cells (APCs). How might this drug impact T regulatory cell (Treg) function?
A scientist is studying the effects of a novel drug on immune regulation. They observe that the drug increases the expression of CD80 and CD86 (B7) on antigen-presenting cells (APCs). How might this drug impact T regulatory cell (Treg) function?
A patient with a chronic autoimmune disorder exhibits a significant decrease in T regulatory cell (Treg) numbers and function. Which of the following therapeutic interventions would be most effective in restoring immune homeostasis?
A patient with a chronic autoimmune disorder exhibits a significant decrease in T regulatory cell (Treg) numbers and function. Which of the following therapeutic interventions would be most effective in restoring immune homeostasis?
Flashcards
T Regulatory Cells (Tregs)
T Regulatory Cells (Tregs)
Subset of CD4+ T cells that suppress lymphocyte activation and proliferation.
Foxp3
Foxp3
Transcription factor essential for the development and function of Tregs.
CTLA-4
CTLA-4
Molecule that competes with CD28 for binding to B7 (CD80/86) on APCs, delivering an inhibitory signal.
IL-2 (Interleukin-2)
IL-2 (Interleukin-2)
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TGF-β (Transforming Growth Factor Beta)
TGF-β (Transforming Growth Factor Beta)
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CTLA-4 Function on APCs
CTLA-4 Function on APCs
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Study Notes
- T regs are a subset of CD4 positive T cells that actively suppress the immune system.
- T regs suppress lymphocyte activation and proliferation.
- The transcription factor Foxp3 regulates T regs.
- T regs limit activation of self-reactive lymphocytes in the periphery and suppress the growth and survival requirements of these T cells.
- T regs are associated with the suppression of autoimmune diseases and are potential targets for immune therapies.
T Reg Function
- T reg interaction with macrophages prevents the secretion of pro-inflammatory cytokines like IL-1 and IL-6.
- T regs prevent macrophages from activating other CD4+ T cells.
- TGF-beta and IL-10 are immune suppressor cytokines secreted from T regs that act on CD4+ T cells and other inflammatory mediators to reduce inflammation.
- T regs can cause destruction of T helper cells using the perforin-granzyme pathway.
T Reg Suppression of Macrophages
- T regs secrete IL-10, which acts directly on macrophages or other antigen-presenting cells.
- T regs have an inhibitory receptor, CTLA-4, which interacts with CD80/86 (B7) on the surface of macrophages, preventing the expression of pro-inflammatory cytokines.
CTLA-4
- CTLA-4 helps regulate and suppress excessive immune activation and maintain peripheral tolerance in T regulatory cells.
- CTLA-4 competes with CD28 on CD4+ T cells for binding with B7 (CD80/86) on antigen-presenting cells.
- CTLA-4 transmits an inhibitory signal, while CD28 binding to B7 provides a stimulatory signal to T cells.
- T reg cells express high levels of CTLA-4, blocking co-stimulation of effector T cells, dampening their activation and proliferation.
- T reg cells can cause the endocytosis and degradation of B7 molecules on APCs through CTLA-4, reducing their ability to activate other T cells.
Foxp3
- The Foxp3 nuclear transcription factor is expressed within T regulatory cells
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