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 range in variation in fluid phase endocytic capability in biopsies from different oral sites. Oral epithelial cells were obtained from both biopsies and single-cell suspensions obtained by brushing the oral cavity. Biopsies in organ culture and single cells in suspension were incubated with fluorescent microspheres of 0.02, 0.1 or 1.0 µm diameter. Endocytosis of fluorescent microspheres was quantitated by flow cytometry and visualised by confocal microscopy. Epithelial cells from all oral sites that were sampled internalised 0.02 µm and 0.1 µm but not 1.0 µm microspheres, with no significant differences observed between oral regions. Single cells from non-cancer patients endocytosed significantly more 0.02 µm microspheres than cells removed from patients with oral cancer. This model may be used to study integrated oral cell function both in health and disease.