Human Peripheral CD4(+) Vδ1(+) γδT Cells Can Develop into αβT Cells

Area of Science:

• Immunology
• T-cell biology
• Adaptive immunity

Background:

• Alpha beta T cells (αβT) are crucial for immunity, but thymic function declines with age.
• Extrathymic T-cell development is proposed but not well understood.
• Gamma delta T cells (γδT), especially Vδ1+ γδT, are found in tissues and have plasticity.

Purpose of the Study:

• To characterize a CD4(+) peripheral Vδ1(+) γδT-cell subpopulation.
• To investigate the potential of this subpopulation to develop into αβT cells.
• To explore the mechanisms and sites of extrathymic T-cell development.

Main Methods:

• Characterization of CD4(+) peripheral Vδ1(+) γδT cells expressing stem-cell markers.
• Ex vivo culture system to observe T-cell development.
• In vivo studies to detect transdifferentiation processes in inflamed tissues.

Main Results:

• Identified a CD4(+) peripheral Vδ1(+) γδT-cell subpopulation with progenitor markers.
• Demonstrated that these γδT cells can develop into functional αβT cells ex vivo and in vivo.
• Observed a transdifferentiation process involving Vδ1(+) γδTCR to αβTCR rearrangement, resembling thymic development.

Conclusions:

• A novel pathway for extrathymic T-cell development from Vδ1(+) γδT cells has been identified.
• This transdifferentiation process occurs readily in vivo in inflamed tissues.
• Findings necessitate a reconsideration of adaptive immune responses in infection, autoimmunity, and cancer.