Maintenance of peripheral naive T cells is sustained by thymus output in mice but not humans.

Parallels between T cell kinetics in mice and men have fueled the idea that a young mouse is a good model system for a young human, and an old mouse, for an elderly human. By combining in vivo kinetic labeling using deuterated water, thymectomy experiments, analysis of T cell receptor excision circles and CD31 expression, and mathematical modeling, we have quantified the contribution of thymus output and peripheral naive T cell division to the maintenance of T cells in mice and men. Aging affected naive T cell maintenance fundamentally differently in mice and men.

Regulated expression of the inhibitory receptor LAIR-1 on human peripheral T cells during T cell activation and differentiation.

The leukocyte-associated Ig-like receptor-1 (LAIR-1) is capable of inhibiting immune cell function through interaction with collagens. LAIR is expressed on the majority of peripheral blood mononuclear cells. The abundant expression of both receptor and ligand calls for regulatory mechanisms to relieve the continuous interaction between collagens and LAIR-1.