Fluid phase endocytosis in oral epithelia: variation with site and effect of cancer

The structure of the oral mucosa has been extensively studied but its cell physiology has been less well characterised. This study aimed to show the r ange in variation in fluid phase endocytic capability in biopsies from diff erent oral sites. Oral epithelial cells were obtained from both biopsies an d single-cell suspensions obtained by brushing the oral cavity. Biopsies in organ culture and single cells in suspension were incubated with fluoresce nt microspheres of 0.02, 0.1 or 1.0 mu m diameter. Endocytosis of fluoresce nt microspheres was quantitated by flow cytometry and visualised by confoca l microscopy. Epithelial cells from all oral sites that were sampled intern alised 0.02 mu m and 0.1 mu m but not 1.0 mu m microspheres, with no signif icant differences observed between oral regions. Single cells from non-canc er patients endocytosed significantly more 0.02 mu m microspheres than cell s removed from patients with oral cancer. This model may be used to study i ntegrated oral cell function both in health and disease.