Marrow colony-forming units: age-related changes in responses to anti-theta-sensitive helper/suppressor stimuli.

Abstract

AbstractEarlier studies with the anemic W/Wv mouse and healthy aged mice have revealed the presence in bone marrow of an anti-θ-sensitive regulatory cell (TSRC) with “helper” function. In experiments presented here, treatment of marrow cells from young mice with anti-θ serum or anti-Ly-1.2 serum and complement had no effect on the number of spleen colonies formed in irradiated recipients; similar treatment of marrow cells from old donors, however, resulted in a 40% reduction in colonies which was reversed if young thymus cells were added to the inoculum. When marrow cells from young or old mice injected 4 days before with SRBC were treated with anti-θ or anti-Ly-2.2 serum and complement, spleen colonies increased by about 50%; treatment of the same cells with anti-Ly-1.2 serum had no significant effect on colony formation. Marrow cells from immunized young and old donors treated with anti-θ serum and complement had no colony inhibitory activity when mixed with marrow from normal young donors; however, the...