Modulation of STRL33 expression levels by isolation and stimulation protocols.

(A) STRL33 levels were quantified on fresh whole blood (CD19⁺ B-cell subset) and after Ficoll-Hypaque gradient purification and overnight incubation in RPMI 1640 supplemented with 10% FCS. Each symbol represents a different donor out of 8 total donors. (B) PBLs from a homozygous ccr5Δ32 donor were Ficoll-Hypaque purified and either left unstimulated (U/S) in media (RPMI 1640 plus 10% FCS) or stimulated with IL-2, PHA/IL-2, or cross-linked anti-CD3/IL-2 (OKT3/IL-2) for 7 days. Cells were then costained for STRL33 and CD25 (as an activation marker). Note the increase in STRL33 levels only on the CD25⁺ subset. Similar data were obtained from 8 donors who had a wild-type for CCR5.