The effect of syngeneic peripheral blood cells on the formation of colonies by normal human bone marrow cells in diffusion chambers in mice

Abstract

This paper describes the influence of cells capable of releasing colony stimulating activity (CSA) in vitro on the formation of granulocytic colonies by normal human bone marrow in diffusion chambers in mice. A carbonyl iron method was used to remove phagocytic cells from normal human bone marrow. This treatment prevented spontaneous colony and cluster formation when the cells were cultured in agar in vitro at initial concentrations of 2-5 x 105 cells per ml. However, non-phagocytic bone marrow cells formed granulocytic colonies when inoculated into diffusion chambers at 105 cells per chamber and cultured in 450 R-irradiated or non-irradiated mice. The formation of granulocytic colonies by carbonyl iron treated marrow in diffusion chamber cultures was not consistently enhanced by the admixture of 1.4 x 105 1500 R-irradiated syngeneic light density blood cells (less than 1.077 g/ml) to the chamber inoculum. In contrast, these cells induced cluster or colony formation when added in the same proportion to the marrow cells in agar cultures in vitro. Addition of 1.4 x 105 1500 R-irradiated high density blood cells(greater than 1.077 g/ml) to the inoculum resulted in a slight, non-significant decrease in the number of colonies in diffusion chambers. The stimulating effect of host irradiation on neutrophilic colony formation was independent of the presence of CSA releasing cells in the chamber inoculum.