Wilton R. Earle

Growth of cell suspensions in tissue culture.

In earlier publications,’preliminary methods and concepts were described by which it had been possible to demonstrate thc proliferation of strain 1,-929 cells as a free-floating cell suspension maintained in a rapidly agitated fluid culture medium. I n these exploratory studies several factors were given special attention. These were: (1) It was obviously necessary to keep the cells in suspension in the nutrient fluid. To accomplish this, rapid agitation of the nutrient fluid was used. To assist in this, viscosity of the culture fluid was slightly increased by addition of 0.1 per cent methyl cellulose CPS 4000. This rapid agitation served also to maintain circulation of the nutrient fluid over the cell surface and to maintain adequate oxygenation of the cell and culture fluid. I n the later study,? a Brunswick type shaker was used. This shaker could handle culture flasks up to 1.5 1. in size. (2) ,4s an extension of earlier studies on the influence of cell population densities on proliferation, it seemed probable that it would be necessary to start the culture with a high population cell density. In exploratory experiments, cells of clone strain L-929 showed rapid cell proliferation under these experimental conditions. The present study gives additional data and development of the concepts and equipment on the growth of certain strains of fixed tissue cells in this type of agitated fluid suspension culture.