Myeloblastic leukemic cells causing suppression of granulopoiesis and excessive binding of colony-stimulating activity

Human myeloid leukaemic cell interactions in vitro with normal myeloid colonies

“…Contrary to expectations, the possibility that an inhibitor of HPCM activity was absorbed was not borne out. Titrations with both absorbed and unabsorbed HPCM suggested that an inhibitor might be present in both preparations at the same volume of 0 3 ml, and mixing unabsorbed and absorbed HPCM did not suppress colony formation below that obtained with absorbed HPCM alone ( Table V) (Chiyoda et al, 1975;Craddock et al, 1978;Cordon et al, 1978;Knudtson & Mortenson, 1976;Morris et al, 1975 It is unlikely that our results are due to poor culture conditions secondary to consumption of nutrients at higher cell concentrations. Colony size was not affected, a finding that has always been seen with poor culture conditions.…”

“…Suppression of normal CFU-C by myeloid leukaemic cells by conditioned media or by extracts has been shown by some (Chiyoda et al, 1975(Chiyoda et al, , 1976Craddock et al, 1978;Gordon et al, 1978;Knudtson & Mortenson, 1976;Morris et al, 1975) and not by others (Bull et al, 1973;Greenberg et al, 1971;Robinson et al, 1971). We report here further experiments to try…”