8] Production of human immune interferon from leukocytes cocultured with exogenous cells

Abstract

Publisher Summary This chapter discusses the production of human immune interferon from leukocytes cocultured with exogenous cells. Human gamma interferon (IFN-γ) is produced in vitro from peripheral blood leukocytes stimulated with mitogens or with the calcium ionophore A-23187. A detailed procedure for the isolation of human leukocytes, the initiation of the leukocytes into 10-liter suspension cell cultures, and induction of the cells with a lectin, phytohemagglutinin-A (PHA), to produce IFN-γ is described. Yields of interferon are augmented by the addition of a phorbol ester to the culture medium and by the cocultivation of the leukocytes with an established human promyloblastic cell line. An average titer of 10,000 reference units/ml of IFN-γ is obtained from human leukocytes cocultivated with HL-60 cells in spinner culture, however, due to the variation of the leukocyte pools, titers ranged from 2500 to 40,000 units/ml. HL-60 cells proliferate in suspension culture; therefore, the time of addition of the cells to the leukocyte induction medium and the final concentration of the HL-60 cells is critical for optimum IFN-γ yields. Human leukocytes, obtained by leukapheresis of normal donors, may be used for the production of human IFN-γ in place of the normal buffy coat leukocytes.