T Cell Differentiation and Cytokine Production Quiz

Cytokines and T Cell Differentiation

• Transforming Growth Factor-beta (TGF-β) stimulates the differentiation of Regulatory T (Treg) cells.
• Interleukin-12 (IL-12) promotes the differentiation of Th1 cells.

Role of Th1 Cells

• Th1 cells play a crucial role in the immune response against intracellular pathogens, such as viruses and some bacteria.
• They activate macrophages and enhance their ability to eliminate pathogens.

Cell-Mediated Immune Responses

• There are two main types:
  • Cell-mediated immunity, which targets intracellular pathogens.
  • Humoral immunity, which targets extracellular pathogens through antibody production.

Primary Cytokine of Th2 Cells

• Interleukin-4 (IL-4) is the primary cytokine produced by Th2 cells, essential for promoting allergic responses and defense against helminths.

Distinct Subsets of CD4+ T Cells

• CD4+ T cells include functionally distinct subsets such as Th1, Th2, and Th17, each producing different cytokines and targeting specific pathogens.

T Cell Recognition of Pathogens

• CD4+ helper T cells (including Th1 and Th2) recognize extracellular antigens presented by Major Histocompatibility Complex (MHC) class II molecules.
• CD8+ cytotoxic T cells recognize cytosolic microbes presented by MHC class I molecules, targeting infected or altered cells.

Primary Role of Treg Cells

• Treg cells maintain immune tolerance and prevent overactive immune responses, thus playing a pivotal role in self-tolerance and preventing autoimmune diseases.

Effector Phase of T Cell Immune Reactions

• Immune reactions involve multiple steps, including:
  • Antigen recognition.
  • T cell proliferation.
  • Differentiation of Naïve T cells.
  • Migration of effector cells to the infection site.
  • Execution of effector functions to combat infection.

Recognition of Cytosolic Microbes

• CD8+ T cells exclusively recognize cytosolic microbes and are vital for targeting infected cells through the MHC class I pathway.