Expression, purification, and in vitro biological activities of recombinant bovine granulocyte-colony stimulating factor

Neutrophils are essential components of the innate immune system and they p lay a critical role in the defense of host against bacterial and fungal inf ections. The colony stimulating factors are a class of glycoproteins that a re required for proliferation. differentiation, and functional activation o f hematopoietic progenitor cells. Granulocyte-colony stimulating factor (G- CSF) is a member of this regulatory family of cytokines that specifically s timulates proliferation and maturation of precursor cells in the bone marro w into fully differentiated and functional neutrophils, G-CSF also modulate s the biological activities of mature neutrophils in circulation. A bovine G-CSF (bG-CSF) cDNA clone (previously isolated and sequenced in our laborat ory) was expressed in Escherichia coli and the biological activities of the solubilized protein from purified inclusion bodies were examined. Flow cyt ometric analysis of membrane antigen density of neutrophils activated with bG-CSF revealed an upregulation in the expression of CD11a (>114%), CD11b ( >148%), CD11c (>87%), and CD18 (>109%). Expression Of L-selectin was decrea sed by more than 43%. There was no change, however, in the expression of CD 14. These findings indicate that recombinant bG-CSF (rbG-CSF) expressed in E. coli is biologically active and exerts the same type of effects on neutr ophils in vitro as those of human G-CSF (hG-CSF). Published by Elsevier Sci ence B.V.