Expression of ligands for NK cell receptors on HHV8-infected cells.

<p>(A) Expression of the indicated ligand was measured by flow cytometry on uninfected (open histograms) and HHV8-infected (gray histograms) HMEC cells (left panels) and KS-derived cells (right panels). Dotted lines represent staining with control isotypes. Histograms are representative of 3–6 independent experiments performed in each cell line. B) K3 and K5 mRNA levels in uninfected or HHV8-infected HMEC and KS-derived cells. Results show the expression level of the K3 and K5 transcripts relative to glyceraldehyde-3-phosphate dehydrogenase (GAPDH) mRNA used as endogenous control, and represent the mean of 2 independent experiments. C) Consecutive sections of paraffin-embedded KS biopsies were stained with antibodies specific for HLA-1 (W6/32), MICA/B (SR99), or isotype control. Representative staining in 2 patients with classical KS out of 5 studied is shown. Staining with hematoxylin-eosin (HE) shows characteristic fascicles of spindle-shaped tumor cells forming the walls of slit-like vascular spaces, associated with mononuclear cell infiltrates. Original magnification x10 (Pt1), x40 (Pt2).