No abstract

Medium conditioned by excised whole lungs from endotoxininjected CS7BL mice was highly active in stimulating hemopoietic colony formation, particularly of granulocytic type, in agar cultures of mouse bone marrow cells. The colony stimulating factor (CSF) in this material had an C Y~-C Y~ electrophoretic mobility, was eluted from calcium phosphate gel by 0.04 M phosphate buffer and had an unusually low apparent Sz0w of 1.9. Sequestered polymorphonuclear neutrophils were excluded as a major source of this CSF. The high specific activity and ease of preparation of lung conditioned medium make it valuable both for the large scale unusual type of CSF.

Possible tissue sources in C57BL mice of the serum factor stimulating colony formation in vitro by mouse bone marrow cells have been investigated.A reproducible technique employing batch chromatography on calcium phosphate gel was developed for the extraction and assay of material with colony stimulating activity from mouse tissues. Sixteen hematopoietic and non-hematopoietic tissues from C57BL mice were found to vary widely in their content of extractable activity. Characterisation of the colony stimulating factors (CSF's) from these tissues by assay of stepped concentrations of eluate showed that CSF's from most tissues were similar in chromatographic behavior, but all differed significantly from those of serum in being both more disperse and more firmly bound to calcium phosphate gel. Male submaxillary salivary gland gave the richest yield of CSF. CSF from this source displayed a greater dispersity on and affinity to calcium phosphate, a lower electrophoretic mobility and a smaller average sedimentation coefficient than that from any other source investigated. Colony morphology appeared to be identical for all tissue sources investigated.