Early Proliferation of Transplanted Spleen Colony-Forming Cells II. Circulation of Cells ∗

Abstract

Summary

Circulation of cells injected into lethally irradiated mice appears to be an important phenomenon in transplantation experiments. The number of colony-forming cells that can be recovered from the lung at 24 hr after transplantation is only about 0.1 the number recovered at 2–4 hr. In spleen this ratio is 0.3, whereas, in bone marrow it is 2. The change in number of transplanted cells in spleen, bone marrow, and blood suggests circulation of cells among the tissues of the host. The proportion of transplanted cells involved in this circulation was uncertain because of changes in the transplantation fraction, f, for cells recoverable from the spleen 4, 24, and 96 hr after transplantation. The changes in f were consistent with the assumption that cells are more susceptible to trauma when they are rapidly proliferating.