ABSTRACT
The aim of this work was to establish a new, simplified in vitro model of the human M-cell. Cocultures of physically separated human intestinal epithelial Caco-2 cells and B-cell lymphoma Raji cells were established. The cocultures were characterized under the criteria of morphology, integrity, expression of M-cell markers and cell adhesion molecules (CAMs), and altered particle transport. Using this construct, the epithelial cells were transformed to cells with an M-cell-like morphology and had altered expression of potential human M-cell markers (alkaline phosphatase down-regulation and Sialyl Lewis A antigen up-regulation). The expression of intercellular adhesion molecule-1 and vascular cell adhesion molecule was altered and there was an increased binding of lectins wheat germ agglutinin and peanut agglutinin with a 40-fold increase in microparticle transport. The particle transport was size-dependent and could be inhibited at 4 degrees C or by replacing the Raji B-cells with Jurkat T-cells. This new coculture model will enable controlled studies of M-cell development and function in vitro.
Subject(s)
Alkaline Phosphatase/biosynthesis , Antigens, Neoplasm/biosynthesis , Cell Adhesion Molecules/biosynthesis , Colon/cytology , Models, Biological , Biological Transport/physiology , Caco-2 Cells , Cell Size , HumansABSTRACT
The effects of postnatal caffeine exposure received through mother's milk were examined in rat pups by administering 0.0125 or 0.05% caffeine solution to the dams throughout lactation. Offspring of caffeine-treated dams showed significantly earlier onset of auditory startle and air righting reflexes. No direct effects of treatment were observed on eight measures of open field activity. At weaning, high-dose caffeine pups exhibited a transient increase in caffeine acceptance in two-bottle taste preference tests and showed cyclic exaggerations in caffeine preference-aversion functions which persisted throughout the 22-day postweaning test period. The caffeine levels in the dams' milk had a 30-fold daily fluctuation reflecting the fluid ingestion pattern related to the light-dark cycle and caffeine elimination rate. Caffeine concentrations in the brains of the pups varied between 0.01 and 9.0 micrograms/g.