IL-1 alpha is produced by T lymphocytes activated via the CD2 plus CD28 pathways

Area of Science:

• Immunology
• Cell Biology

Background:

• Resting T cells activate via the T cell receptor (TCR) complex.
• Surface molecules CD2 and CD28 also mediate T cell activation and proliferation through monoclonal antibodies (mAbs).

Purpose of the Study:

• To investigate the cytokine production profile of T cells activated by CD2 and CD28 co-stimulation.
• To determine if combined CD2 and CD28 activation influences the expression and secretion of specific cytokines, particularly monokines.

Main Methods:

• Purified resting T cells were activated using monoclonal antibodies (mAbs) targeting CD2 and CD28.
• Expression and secretion of cytokines, including IL-1 alpha, IL-1 beta, IL-6, and TNF-alpha, were analyzed.

Main Results:

• Combined CD2 and CD28 activation uniquely induced the expression and secretion of IL-1 alpha, a monokine.
• Neither IL-1 beta nor IL-6 were produced by activated T cells.
• Tumor Necrosis Factor-alpha (TNF-alpha) was transiently expressed by T cells activated by either CD2 or CD28 alone, but showed higher levels and prolonged kinetics with combined CD2 plus CD28 activation.
• Prolonged IL-1 alpha gene expression correlated with monocyte-independent, long-lasting T cell proliferation.

Conclusions:

• Co-stimulation via CD2 and CD28 on T cells leads to the secretion of IL-1 alpha, a cytokine typically associated with monocytes.
• This T cell-derived IL-1 alpha may contribute to sustained T cell proliferation independently of monocytes.
• Secretion of monokines by activated T cells could have regulatory roles in immune responses and potentially contribute to autoimmune diseases.