Interleukin 10 is a human T cell growth factor in vitro

Area of Science:

• Immunology
• Cell Biology

Background:

• Interleukin-10 (IL-10) is known for its immunosuppressive functions, including inhibition of lymphocyte proliferation.
• Previous studies highlight IL-10's role in blocking T cell activation and stimulation.

Purpose of the Study:

• To investigate the dual role of IL-10 in T cell responses, examining both its inhibitory and potential proliferative effects.
• To characterize the subsets of T cells that respond to IL-10 stimulation.

Main Methods:

• Mixed lymphocyte cultures (MLC) and T cell clone cultures (TCC) were utilized.
• Proliferative responses were assessed using tritiated thymidine incorporation.
• Neutralizing antisera against IL-10, IL-2, and IL-4 were employed to dissect cytokine involvement.
• Flow cytometry was used to analyze T cell subsets (CD4+, CD8+, TCR1, TCR2).

Main Results:

• IL-10 enhanced the viability of lymphocytes surviving mixed lymphocyte cultures.
• A subset of IL-2-dependent T cell lines proliferated in response to IL-10 alone in a dose-dependent manner.
• CD4+ T cell receptor alpha, beta (TCR2) TCC and T cell receptor gamma delta (TCR1) TCC showed proliferative responses to IL-10, with varying degrees of strength.
• CD8+ TCR2 TCC exhibited limited proliferation in response to IL-10.

Conclusions:

• IL-10 exhibits a dual function, inhibiting T cell activation while also promoting clonal expansion in specific preactivated T cell subsets.
• The proliferative effect of IL-10 is specific to certain T cell populations, including CD4+ and TCR1 T cells.
• These findings expand the understanding of IL-10's complex regulatory role in T cell-mediated immunity.