Figure 4. Absence of BODIPY-glycolipids from TWEEs.

Sections of mucosal explants cultured for 1 h in the presence of BODIPY-lactosylceramide (Bod-laccer), BODIPY-GM₁ (Bod-GM₁), or BODIPY-GM₁ and CTB (Bod-GM₁+CTB). BODIPY-lactosylceramide strongly labeled the brush border (arrows), but distinct subapical punctae indicative of TWEEs were not detected. BODIPY-GM₁ alone only weakly labeled the brush border and not the TWEEs, but in the presence of CTB a distinct, patchy labeling of the brush border was seen. In addition, the subapical TWEEs were prominently labeled. Bars, 20 µm.