CONTACT INHIBITION OF GROWTH (Latin inhibere to hold, stop) — ability of cells in culture of fabric to stop the movement and reproduction at contact with other cells and formation of a monolayer. For the first time the phenomenon To. and. river it was revealed in 1953 Aberkrombi and Geysman (M. of Abercrombie, J. E. M of Heaysman) in the course of overseeing by culture of fibroblasts of a ventricle of heart of a chicken embryo in a hanging drop.
Fibroblasts in culture of fabric move on substrate thanks to undulations of an undulating membrane. In a few minutes after visible contact of cells undulations of a membrane stop, the cell stops, there comes the contact inhibition of the movement. The contact of cells leads to suppression of the internal locomotory mechanism of a cell. The periblast of a cellular membrane remains at the same time almost not changed, the inner layer of a membrane adjoining on cytoplasm is considerably thickened; quite often the microfibrils reminding roots of ciliary cilia depart from it in depth of cytoplasm. The structure formed by two reinforced plasma membranes and the dense substance concluded between them received the name of a desmosome. Between the contacting cells the space in 20 — 50 nanometers remains, it is rare — less than 10 nanometers. This space contains a mukoproteidny or glikoproteidny complex in which cytoplasmatic outgrowths press.
The contact inhibition of the movement depends on many factors, in particular on character of the intercellular environment, density of cell population and type of the reacting cells. So, cells of a chicken are characterized by big contact inhibition of the movement, than a cell of a mouse.
Important property of interaction of cells in culture is the termination of reproduction at achievement of a certain population density and formation of a monolayer (fig. 1) — contact inhibition of reproduction, the mechanism to-rogo is not opened.
To. and. the river is followed considerable biochemical, reorganizations in a cell: in it intensity of synthesis of RNA (by 85 — 95%) and a squirrel sharply decreases (for 50 — 70%), polysom disappear, synthesis of DNA almost completely stops. The phenomenon To. and. river it is reversible. Disturbance of contact between cells, emergence of a free surface leads to formation of a new undulating membrane and resuming of the movement. The cell which resumed the movement is again capable to enter a mitotic cycle. For a short time To. and. the river can be removed by addition of fresh serum on Wednesday of cultivation.
The majority of malignizirovanny cells loses ability to To. and. river. In malignizirovanny cells there is no contact inhibition of the movement, they crawl at each other, forming multilayer cellular layers (fig. 2) in which it is possible to find mitotic the sharing cells.
Oppression of reproduction of cells owing to suppression of synthesis of DNA is revealed at impact on cells of the inhibitor emitted from various bodies and zooblasts (skin, a liver, kidneys, lungs, blood serum), and also at influence of the environment, in a cut granulocytes grew. These organospetsifichesky, but vidonespetsifichesky inhibitors were called chalones (see). The analytical electrophoresis showed that chalones are acid proteins, they inhibit synthesis of DNA in cells, reduce process of graft rejection, oppress reaction explant against the owner, transformation of lymphocytes in the presence of phytohemagglutinin (FGA), education 19S of hemolysin against erythrocytes of a ram.
Bibliography: Vasilyev Yu. M. and Malenkov A. G. Cellular surface and reactions of a cell, L., 1968, bibliogr.; A. Poverkhnost's palikar of a cell and its microenvironment, the lane with fr., M., 1975; Trinkaus Dzh. From cells to bodies, the lane with English, M., 1972; Abercrombie M. Contact inhibition, Nat. Cancer Inst. Monogr., v. 26, p. 249, 1967, bibliogr.; Mac Yittie T. J. a. Me Carthy K. F. Inhibition of granulopoesis in diffusion chambers by a granulocyte chalone, Exp. Hemat., v. 2, p. 182, 1974.
A. M. Amchenkova.