Natural killer activity and suppressor cells in irradiated mice repopulated with a mixture of cells from normal and 89Sr-treated donors
Levy, E.M.; Kumar, V.; Bennett, M.
Journal of Immunology 127(4): 1428-1432
1981
ISSN/ISBN: 0022-1767 PMID: 6456306 Document Number: 169485
Mice injected with 89Sr have fairly normal B and T cell function, but are abnormal in that they lack natural killer (NK) activity and other functions that requre an intact bone marrow. These mice also have an increased potential for suppressor cell activity. Spleen cells from 89Sr-treated mice were previously shown to transfer low NK activity and increased suppressor cell function to lethally irradiated syngeneic recipients. To investigate the mechanisms involved in perpetuating these defects, groups of normal animals were irradiated and infused with mixtures of spleen cells from 89Sr-treated mice and normal spleen or bone marrow cells. Recipients were assayed for their NK activity and suppressor cell function 5-14 wk later. The addition of normal cells in the donor inoculum resulted in normal NK activity. Low NK activity in 89Sr-treated mice was thus apparently not due to the presence of a suppressor cell that prevented NK cell generation. Low NK activity in recipient mice could be boosted by interferon inducers, indicating that NK activity in the recipients was not due to a lack of interferon-sensitive pre-NK cells. Suppressor cell function in recipient mice depended on the type and number of normal cells in the donor inoculum. Bone marrow cells were very efficient in overcoming the tendency to produce suppressor cells. It took approximately 20 times more normal spleen cells to produce the same results. The implications of these findings are discussed.