[The importance of the density of spleen cell suspensions in cultures for development of immune reactions].

A relationship was revealed between the number of cells in the suspension of the splenic tissue taken for induction of primary immunization of the reaction outside the organism and the number of the plaque-forming cells (PFC) formed by the end of incubation. It was shown that with increase of the cell density in the culture in the bottom of the incubation flask there was a 10-100 fold decrease of the PFC response; as to the cell viability--it was not affected or decreased but slightly. This effect was observed in using sheep red blood cells and water-soluble antigen extracted from them as an antigen. The effect was independent of shortage of the antigen or of the nutrient substances; it was accompanied by a general reduction of the 3H-thymidine incorporation into cultured cells.