Granulocytic colonies on macrophage-coated cellulose acetate membranes (CAM) in S1/S1dmice.
The kinetics of formation of granulocytic colonies on macrophage-coated cellulose acetate membranes (CAM) were investigated in Sl/Sld mice, which have a genetic defect in their hematopoietic microenvironment. CAM were left in the peritoneal cavity of mice for 7 days to become coated with peritoneal cells. The mice were then sublethally irradiated to suppress endogenously derived granulocytic colonies, and bone marrow cells were injected i.p. within 1--2 hr irradiation. During the next 7 days, peroxidase-positive granulocytic colonies appeared on CAM. The number of colonies on CAM in Sl/Sld mice at 7 days was consistently less than that from littermate +/+ mice. Since it appeared that the CAM in the Sl/Sld provided an inferior microenvironment to that of the +/+, the effect of raising a CAM in one genotype and transferring it to another was investigated. CAM raised in +/+ or in Sl/Sld were transferred to an irradiated +/+ or Sl/Sld following which cells were injected into the secondary host and colonies determined subsequently. The number of granulocytic colonies on CAM was influenced primarily by the type of secondary host. Colony number was consistently less in the secondary Sl/Sld host than in the +/+ host whether the primary host was a Sl/Sld or a +/+. These observations confirm the concept of a microenvironmental defect in Sl/Sld mice. In addition, the studies indicate that the microenvironment on a CAM can be modified by a secondary host and suggest that "remodeling" of CAM may be a continuous, kinetic process.
D000818:Animals; D002482:Cellulose; D005260:Female; D005838:Genotype; D006098:Granulocytes / Q000166:cytology* / Q000254:growth & development; D008264:Macrophages; D008297:Male; D008566:Membranes; D051379:Mice
D002482:Cellulose