Balancing naïvete with experience
Before killer T cells (usually bearing the CD8 marker) are exposed to foreign pathogens, they are considered "naïve." After fighting an infection a population called "memory" CD8 T cells lingers and provides a much faster response should the pathogen resurface. A balance of naïve and memory cells must be maintained in the body so that naïve cells can fight new infections and memory cells can to react to old foes. How the naïve and memory CD8 T cell pools are regulated is poorly understood, although recent evidence suggests immune modulators, called cytokines, may play a role in maintaining levels of memory cells.
In the November issue of Nature Immunology (Vol. 1, No. 5), scientists from Minneapolis, Minnesota, show that the cytokine interleukin 7 (IL-7) plays multiple roles in maintaining the right numbers of naïve and memory T cells. IL-7 was required to regulate the survival of naïve T cells in the host. It was also needed for the generation of memory CD8+ T cells. In addition, the levels of CD8+ memory T cells in the T cell pool were partially dependent on IL-7. Thus, IL-7 is critical for maintaining a healthy balance of naïve and memory T cells in the body.
University of Connecticut
School of Medicine
Department of Medicine
Division of Rheumatic Diseases
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Farmington, CT 06030-1310
(C) Nature Immunology press release.
Message posted by: Trevor M. D'Souza