as to the cellular origin of the c3-stimulating factor ( s ) , several observations were made : ( a ) in separate cultures containing either t-cells or monocyte-enriched populations from the same sample of blood mononuclear cells , no activity was detected in the presence or absence of phytohemagglutinin , ( b ) conditioned media from each of these cultures could not substitute for the corresponding intact cell populations , and ( c ) the addition of purified t-cells to the monocyte-enriched population in the presence of phytohemagglutinin restored the production of the stimulating activity by the mixed culture .
C0007634
cellular
C1321301
blood mononuclear cells