T Cell Differentiation and Function

A set of 50 flashcards covering key concepts and details from the lecture on T cell differentiation and function.

What are the signals required for T helper cell activation?

Signal 1: TCR + antigen bound to MHC; Signal 2: Costimulation; Signal 3: IL-2 + IL-2R = proliferation.

Which cytokine promotes proliferation in T cell activation?

IL-2.

What are the polarizing cytokines for Th1 cells?

IL-12, IFN-γ, and IL-18.

What master transcriptional regulator is associated with Th1 cells?

T-Bet.

What are the effector cytokines of Th1 cells?

IFN-γ and TNF.

What is the main role of Th1 cells?

Combat intracellular pathogens by activating macrophages.

Which cytokines are involved in driving Th2 cell differentiation?

IL-4, IL-5, and IL-13.

What is the master transcriptional regulator for Th2 cells?

GATA3.

What are the effector functions of Th2 cells?

Combating helminth infections and activating eosinophils.

What are the consequences of Th2 cell activation?

Allergy and tissue inflammation.

Which cytokines are effective for Th17 cell differentiation?

IL-6 and TGF-β.

What is the master transcriptional regulator for Th17 cells?

RORγt.

What are the effector cytokines produced by Th17 cells?

IL-17A and IL-22.

What is the role of Th17 cells?

Combat extracellular pathogens and contribute to autoimmune conditions.

What condition is associated with dysfunctional Th17 cells?

Job Syndrome, leading to hyper-IgE syndrome.

Which cells are regulated by T regulatory cells?

Naïve T cells and other immune cells.

What are the primary functions of T regulatory cells?

Suppressive effects on immune responses and secretion of anti-inflammatory cytokines.

What is the role of CTL in the immune system?

Induce cell death in infected or cancerous cells.

How do cytotoxic T lymphocytes (CTL) induce cell death?

By releasing cytotoxins, producing TNF-α, and triggering Fas/FasL interactions.

What is the importance of CD40/CD40L interaction in Th1 cells?

Licenses dendritic cells to present antigens to naïve CD8+ T cells.

What happens when inappropriate Th cell subsets are activated?

Can lead to autoimmune diseases and ineffective immune responses.

Which cytokine enhances the function of macrophages and granule mixing?

IFN-γ.

What is the average lifespan of effector Th cells?

Short-lived after the primary immune response.

Describe cross-regulation of Th1 and Th2 cells.

Expression of one master transcriptional regulator blocks the expression of the other.

Why is TGF-β critical in T cell differentiation?

It influences the differentiation of Th17 and regulatory T cells.

What is the function of anti-inflammatory cytokines?

To regulate the immune response and maintain homeostasis.

What type of immunity do Th1 cells predominantly provide?

Cell-mediated immunity.

What type of pathogens do Th2 cells mainly respond to?

Extracellular parasites such as allergens and helminths.

What initiates the differentiation of Th cells?

Antigen recognition and the presence of polarizing cytokines.

What role does TGF-β play in Treg function?

Suppresses immune responses and promotes tolerance.

What is the effect of IL-17A produced by Th17 cells?

Increases inflammation and recruitment of neutrophils.

What are the potential consequences of Th1 responses in leprosy patients?

Granuloma formation and limited damage to skin and nerves.

How can cytokine patterns help in classifying immune responses?

Based on the levels of Th1 vs. Th2 cytokines measured.

What do CTLs need to become activated?

Specific antigen recognition and costimulatory signals.

What is linked suppression in T regulatory cells?

Tregs suppress other T cells through interaction with APCs and distinct Ag-MHC complexes.

What can excessive activation of Th cells lead to?

Autoimmunity and chronic inflammation.

What is a significant challenge in Th17 differentiation?

Finding the balance between Th17 and Treg cells.

What is the primary defensive mechanism of Th1 cells?

Targeting and eliminating intracellular pathogens.

Describe the role of perforin in CTL-mediated cytotoxicity.

Forms pores in the target cell membrane allowing entry of granzymes.

How do Th cells contribute to antibody production?

By providing help to B cells through cytokines and direct interactions.

How is Th cell differentiation influenced by the type of pathogen present?

Different pathogens induce specific cytokine environments that guide Th differentiation.