Tetraspanin expression at the cell surface of monocyte-derived immature DCs. (A) Expression of MHC class I, MHC class II, CD40, CD80, CD83, and CD86 on immature and mature DCs (shaded histograms). Isotype-matched control immunoglobulin labeling is shown in open histograms. (B) Expression of CD63, CD9, CD81, CD82, and CD151 on immature and mature DCs (shaded histograms). Isotype-matched control immunoglobulins labeling is shown in open histograms. Obtention and FACS analysis of human immature and mature DCs were performed as described in “Materials and methods.” A total of 10 000 events were analyzed in each case. The histograms shown are representative of at least 4 experiments. (C) Microphotographs illustrating the pattern of CD63 expression before cell permeabilization (left) and of CD63 (middle) and CD82 (right) expression after cell permeabilization, observed by confocal microscopy in immature DCs. Objective lenses: C-Apochromat 63 ×/1.2 numerical aperture (NA), water.