Interleukin-2 expression by a subpopulation of primary T cells is linked to enhanced memory/effector function

Area of Science:

• Immunology
• Cell Biology
• T cell activation

Background:

• Single-cell studies reveal intraclonal heterogeneity in activated T cell cytokine production.
• Understanding this heterogeneity is crucial for comprehending T cell fate and immune responses.

Purpose of the Study:

• To investigate the implications of cytokine heterogeneity for T cell fate.
• To track interleukin-2 (IL-2) producing and non-producing T cells during differentiation.

Main Methods:

• Development of a transgenic model using an IL-2 promoter-green fluorescent protein (GFP) reporter.
• Tracking IL-2+ and IL-2- T cells from naive precursors through primary and secondary responses.
• Assessing proliferative capacity, antigenic sensitivity, and effector cytokine expression in vitro and in vivo.

Main Results:

• Antigen-activated IL-2+ and IL-2- T cells exhibited similar proliferative capacities in primary responses.
• T cells expressing IL-2 during primary responses showed heightened antigenic sensitivity in secondary responses.
• These IL-2-expressing cells also displayed increased effector cytokine expression in secondary responses.

Conclusions:

• Cytokine heterogeneity during a primary T cell response leads to varied secondary responses.
• Enhanced memory and effector functions in secondary responses are associated with T cells that previously exceeded the IL-2 gene transcription threshold.