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Phytohemagglutin-stimulated human T cell: prothymosin alpha as an accessory signal

O J Cordero1, C S Sarandeses, M Nogueira

  • 1Department of Biochemistry and Molecular Biology, Faculty of Biology, University of Santiago, Santiago de Compostela, Spain.

Journal of Biological Regulators and Homeostatic Agents
|January 1, 1990
PubMed

Insights

Prothymosin alpha (Pro alpha) and thymosin alpha 1 (alpha 1) modulate human lymphocyte proliferation, with effects varying by stimulation and dose. Thymosin beta 4 (beta 4) showed no impact, serving as a control.

Area of Science:

  • Immunology
  • Molecular Biology

Background:

  • Thymic peptide factors are crucial for regulating normal human lymphocyte proliferation.
  • Understanding the specific roles of thymosins in immune responses is essential for therapeutic development.

Purpose of the Study:

  • To investigate the impact of Prothymosin alpha (Pro alpha) on phytohemagglutinin (PHA)-stimulated peripheral blood mononuclear cells (PBMC) and peripheral blood lymphocyte cultures (PBLC).
  • To evaluate the role of thymosin alpha 1 (alpha 1) and thymosin beta 4 (beta 4) in lymphocyte proliferation.
  • To elucidate the involvement of macrophages and interleukin-1 (IL-1) in Pro alpha-mediated lymphoproliferation.

Main Methods:

  • Culturing of PHA-stimulated PBMC and PBLC with varying concentrations of Pro alpha, alpha 1, and beta 4.
  • Assessing lymphoproliferative responses under different stimulation levels and preincubation times.
  • Investigating the role of monocytes and monocyte-derived supernatants.
  • Evaluating the effects of IL-1 and an IL-2 receptor antagonist (Tac Ag) on T cell proliferation.

Main Results:

  • Pro alpha and alpha 1 demonstrated dose- and time-dependent modulation of PBMC proliferation.
  • Thymosin beta 4 did not affect lymphocyte proliferation, validating its use as a control peptide.
  • Macrophage presence was critical for Pro alpha-induced lymphoproliferation.
  • IL-1 enhanced Pro alpha's helper effect, and this combined effect was blocked by an IL-2 receptor antagonist, indicating an IL-2-dependent pathway.

Conclusions:

  • Pro thymosin alpha and thymosin alpha 1 are potent modulators of human lymphocyte proliferation, with their activity influenced by cellular context and stimulation.
  • Macrophage-derived factors and IL-2 signaling pathways are integral to the lymphoproliferative effects of Pro alpha.
  • Thymosin beta 4 serves as a useful control peptide in studies of thymosin function.

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