Figure 2. Circadian Bioluminescene Recordings from Primary Human Blood Cells, Fibroblasts, and Keratinocytes.

(A) For two different individuals, 50,000 non-immortalized adult primary human skin fibroblasts were infected with lentiviral reporter vectors. Four days after infection, cells were shocked with dexamethasone, and circadian rhythms were measured by real-time luminometry.

(B) For two different individuals, 50,000 human blood monocytes were treated as in (A).

(C) A skin biopsy was taken from one individual, and 50,000 fibroblasts were treated as in (A) and (B). In parallel, hairs were plucked until a hair was withdrawn that contained hair root keratinocytes clinging to the proximal end. These were cultivated and amplified to 50,000 cells, then infected and measured identically to fibroblasts.