Lecture 10 t cells 2

These flashcards cover key concepts and mechanisms of T cell subsets, their functions, and their roles in immunity and autoimmunity as discussed in the lecture.

What role do CD4 T cells play in the immune system?

CD4 T cells, or T helper cells, help other immune cells perform their functions, primarily by releasing cytokines.

What is the function of CD8 T cells?

CD8 T cells are primarily responsible for killing virally infected cells and cancer cells.

How are CD4 T cells differentiated?

CD4 T cells are differentiated into various subsets based on signals received during their activation, including cytokines and co-stimulation.

What are the main CD4 T cell subsets discussed in the lecture?

The main subsets are Th1, Th2, Th17, and T follicular helper (TfH) cells.

What cytokine is primarily involved in the differentiation of Th1 cells?

IL-12 is the key cytokine for driving Th1 differentiation.

what is primary function of Th1 cells

important in cell mediated immune responses against intracellular pathogens such as viruses and bacteria.

What is the primary function of Th2 cells?

Th2 cells are important in immune responses against large extracellular pathogens like helminths and they help stimulate B cell antibody production. humoral immunity

Which cytokine is critical for Th2 differentiation?

IL-4 is the primary cytokine that promotes Th2 differentiation.

What are the master regulatory transcription factors of Th2 cells?

The master regulators for Th2 differentiation are GATA3 and STAT6.

What key cytokine do Th17 cells produce?

Th17 cells produce IL-17.

What is the function of T follicular helper (TfH) cells?

TfH cells help B cells produce high-affinity antibodies and promote processes such as class switching and somatic hypermutation.

How do TfH cells assist in B cell activation?

They engage B cells through CD40-CD40L interactions and secrete IL-21 to promote B cell functions.

What is the role of regulatory T cells (Tregs) in the immune system?

Tregs maintain immune tolerance and suppress autoreactive T cell responses to prevent autoimmunity.

What transcription factor is essential for Treg function?

FOXP3 is the master regulator essential for Treg differentiation.

What can result from insufficient regulatory T cells?

Insufficient Tregs can lead to autoimmune diseases due to unchecked effector T cell activation.

What autoimmune disease is associated with a defect in FOXP3?

IPEX syndrome is a rare autoimmune disease resulting from a defect in the FOXP3 gene.

What is the relationship between Th17 cells and autoimmunity?

Th17 cells are associated with several autoimmune diseases due to their pro-inflammatory functions.

How can CD4 T cell subsets exhibit plasticity?

Some CD4 T cell subsets can change their function and characteristics in response to different inflammatory environments.

What role do cytokines play in T cell differentiation?

Cytokines influence which transcription factors are activated, guiding T cells to differentiate into specific subsets.

What happens in multiple sclerosis related to T helper cells?

In MS, Th17 and Th1 cells infiltrate the central nervous system, contributing to inflammation and tissue damage.

What is the effect of excessive Th2 activation?

Excessive Th2 activation can result in allergic reactions and responses to benign antigens.

What subsets of CD4+ T cells can develop after antigen stimulation?

The main subsets of CD4+ T cells that can develop after antigen stimulation are Th1, Th2, Th17, Treg, and Tfh cells.

What cytokines drive the development of Th1 cells?

The development of Th1 cells is primarily driven by IL-12 and IFN-γ.

What cytokines drive the development of Th2 cells?

The development of Th2 cells is primarily driven by IL-4.

What cytokines drive the development of Th17 cells?

The development of Th17 cells is primarily driven by IL-6 and TGF-β.

What cytokines drive the development of Treg cells?

The development of Treg cells is influenced by IL-2 and TGF-β.

What are the main functions of Th1 cells?

Th1 cells primarily promote cellular immunity and are involved in the response to intracellular pathogens.

What are the main functions of Th2 cells?

Th2 cells are mainly involved in humoral immunity and help in response to extracellular pathogens.

What are the main functions of Th17 cells?

Th17 cells play a critical role in inflammation and defense against extracellular bacteria and fungi.

What are the main functions of Treg cells?

Treg cells are essential for maintaining immune tolerance and preventing autoimmunity.

What are the main functions of Tfh cells?

Tfh cells assist in the activation of B cells and the formation of germinal centers for antibody production.

What signals are required for naïve T cell activation?

Naïve T cell activation requires two main signals:

1. Signal 1: Interaction between the T cell receptor (TCR) and the specific peptide presented by Major Histocompatibility Complex (MHC) molecules on antigen-presenting cells (APCs).
2. Signal 2: Co-stimulatory signals provided by the interaction of CD28 on the T cell with B7-1 (CD80) or B7-2 (CD86) on the APC.

What are the primary mechanisms by which CD8+ T cells kill virus-infected host cells?

CD8+ T cells kill virus-infected host cells primarily through two mechanisms:

1. Cytotoxic granule release: CD8+ T cells release perforin and granzymes, which create pores in the target cell membrane and induce apoptosis.

2. Fas ligand (FasL) interaction: CD8+ T cells express FasL, which binds to Fas on the infected target cell, triggering a cascade that leads to apoptosis.