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An instructive component in T helper cell type 2 (Th2) development mediated by GATA-3
J D Farrar1, W Ouyang, M Löhning
1Department of Pathology and Center for Immunology, Howard Hughes Medical Institute, Washington University School of Medicine, St. Louis, MO 63110, USA.
The Journal of Experimental Medicine
|March 10, 2001
Summary
Cytokines instruct T helper cell development, not just select pre-committed cells. This study shows interleukin-4 (IL-4) can redirect committed cells, supporting an instructive model for T helper cell type 1 (Th1) and Th2 differentiation.
Area of Science:
- Immunology
- Cell Biology
- Molecular Biology
Background:
- Naive CD4(+) T cells differentiate into T helper cell type 1 (Th1) or Th2 phenotypes, influenced by cytokines like interleukin-12 (IL-12) and interleukin-4 (IL-4).
- The precise mechanism governing this differentiation—whether cytokines instruct developing cells or select pre-committed cells—remains unclear.
Purpose of the Study:
- To differentiate between instructive and selective models of T helper cell differentiation.
- To investigate the role of cytokines in programming cell fate decisions in CD4(+) T cell progenitors.
Main Methods:
- Utilized surface affinity matrix technology to isolate cytokine-secreting progenitor cells.
- Employed retroviral-based tagging to track individual progenitor cell fate decisions at clonal and population levels.
- Analyzed phenotype redirection in response to IL-4 and assessed the impact of GATA-3 expression on progenitor differentiation.
Main Results:
- Observed IL-4-dependent redirection of cell phenotype, even in cells already committed to a non-IL-4-producing fate, contradicting the selective model.
- Direct evidence for instructive differentiation was obtained through retroviral tagging of naive progenitors with the Th2-specific transcription factor GATA-3.
- Found no evidence supporting the selective outgrowth of cells pre-committed to either Th1 or Th2 fates.
Conclusions:
- Selection is not the exclusive mechanism driving Th1/Th2 differentiation.
- Data strongly support an instructive model where cytokines program cell fate decisions, influencing transcriptional programming for differentiation.