NK cells are essential for health, yet little is known about @entity1 NK turnover in vivo. In both young and elderly @entity1 , all NK subsets proliferated and died more rapidly than T cells. @entity2940 (bright) NK cells proliferated rapidly but died relatively slowly, suggesting that proliferating @entity2940 (bright) cells differentiate into @entity2940 (dim) NK cells in vivo. The relationship between @entity2940 (dim) and @entity2940 (bright) proliferating cells indicates that proliferating @entity2940 (dim) cells both self-renew and are derived from proliferating @entity2940 (bright) NK cells. Our data suggest that some dying @entity2940 (dim) cells become @entity4071 (+) @entity2940 (-) NK cells and that @entity4071 (-) @entity2940 (low) NK cells respond rapidly to cellular and cytokine stimulation. We propose a model in which all NK cell subsets are in dynamic flux. About half of @entity2940 (dim) NK cells expressed @entity4755 , which was weakly associated with low proliferation. Surprisingly, @entity4755 expression was associated with higher proliferation rates in both @entity405 (+) and @entity405 (-) T cells. Therefore, @entity4755 is not a reliable marker of senescent, nonproliferative T cells in vivo. @entity9707 expression declined with age on both NK cells and T cells. @entity31792 expression increased with age on T cells but not on NK cells. Although the percentage of @entity2940 (bright) NK cells declined with age and the percentage of @entity2940 (dim) NK cells increased with age, there were no significant age-related proliferation or apoptosis differences for these two populations or for total NK cells. In vivo @entity1 NK cell turnover is rapid in both young and elderly adults.

XXXX NK cells proliferate and die in vivo more rapidly than T cells in healthy young and elderly adults.

@entity1 :: ('9606', 'Species') :: ['women', 'human'] @entity9707 :: ('3821', 'Gene') :: ['NKG2A'] @entity2940 :: ('4684', 'Gene') :: ['CD56'] @entity4755 :: ('27087', 'Gene') :: ['CD57'] @entity4071 :: ('2214', 'Gene') :: ['CD16'] @entity31792 :: ('100132285', 'Gene') :: ['Killer cell Ig-like receptor'] @entity405 :: ('925', 'Gene') :: ['CD8']
@entity1 :: (9606,Species) :: ['Human']
