What is the Difference Between TH1 and TH2 Helper Cells?

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TH1 and TH2 helper cells are two distinct subsets of CD4+ T cells that play crucial roles in the immune response. They are characterized by their specific cytokine expression patterns and functions.

TH1 helper cells:

  • Produce interleukin (IL)-2, gamma-interferon (IFN-gamma), and tumor necrosis factor-beta (TNF-beta).
  • Activate macrophages and are responsible for cell-mediated immunity and phagocyte-dependent responses.
  • Mainly develop following infections by intracellular bacteria and some viruses.
  • Contribute to delayed-type hypersensitivity reactions.
  • Involved in many organ-specific autoimmune diseases, such as rheumatoid arthritis and insulin-dependent diabetes mellitus.

TH2 helper cells:

  • Produce IL-4, IL-5, IL-6, IL-10, IL-13, and IL-9.
  • Induce strong antibody production, eosinophil activation, and are excellent helpers for B-cell antibody secretion, particularly IgE responses.
  • Predominate in response to infestations by gastrointestinal nematodes.
  • Play an important role in providing protection against certain extracellular pathogens, such as bacteria and a variety of parasites.

Mutual cross-regulation between TH1 and TH2 cells has been reported, with TH1 cells influencing each other via IFN-gamma and TH2 cells via IL-10. The different functional subsets of TH cells arise post-thymically, but the factors affecting differentiation of TH precursors into the TH1 or TH2 subsets are still unclear.

Comparative Table: TH1 vs TH2 Helper Cells

Here is a table summarizing the differences between TH1 and TH2 helper cells:

Characteristic TH1 Cells TH2 Cells
Secreted Cytokines IFN-γ, IL-2, IL-3, TNF-α, TNF-β IL-4, IL-10, IL-5, IL-9, IL-13
Characteristic Cytokines IFN-γ IL-4
Adjustment Factors IFN-γ, IL-12 IL-4, IL-13, IL-5
Function Activate cellular immune response, inhibit macrophage activation, stimulate B cells to produce IgM, IgG1 Stimulate humoral immune response, promote B cell proliferation, induce antibody production, induce differentiation and proliferation of mast cells and eosinophilic leukocytes

TH1 and TH2 helper cells are differentiated from common T cell helper precursor (Thp) and play important roles in the immune system. TH1 cells stimulate cellular immune response, while TH2 cells stimulate humoral immune response. The balance between TH1 and TH2 cells is crucial for maintaining a healthy immune system, and an imbalance can lead to diseases such as allergies, asthma, autoimmune diseases, and inappropriate immune responses.