Fractionation of antibodies to L-cell colony-stimulating factor by affinity chromatography

Purified L-cell colony-stimulating factor (CSF) was coupled to cyanogen- bromide-activated Sepharose and used to selectively fractionate antibodies to this factor. With the use of a simplified two-step washing and elution technique, there was 50%--70% binding of the anti- CSF, with recovery of 60%--100% of the bound material. Both the native antiserum and purified anti-CSF fractions were inhibitory to murine granulocyte-macrophage colony formation. The purified antibodies contained only IgG and were reduced in protein concentration to 0.1% of the serum IgG values. These fractions should prove useful tools for the study of granulocyte and macrophage differentiation.