Studies on the proliferative capacity of mouse spleen cells in serial transplantation

The ageing of mouse spleen cells in vivo was investigated by determining the size distribution of cell volumes. It was found that ageing is accompained by an increase in cell volume which is in agreement with published data on ageing for a number of cell types both in vivo and in vitro. After the first transplantation into irradiated hosts the size distribution of spleen cells proves to be more heterogeneous which may affect the proliferative capacity. After the fifth transplantation, when the cell population is three years old, the parameters of the volume distributions of spleen cells agree better with the data from middle-aged mice than with the data from old-aged mice. Further it was found that at least six serial transplantations are possible if the interval between passages is long. Therefore our data do not show an intrinsic limited proliferative capacity of these cells.