Abstract: Methods and apparatus are provided for growing both suspension type cells and anchorage dependent cells in airlift bioreactors. A packing means, such as stainless steel wool, is provided in the growth chamber of the bioreactor to increase cell density by trapping suspension cells or acting as a solid support for anchorage depended cells without interfering with gentle circulation of liquid growth medium in the bioreactor.

Abstract: Method and apparatus are provided for immobilizing and growing cells in airlift bioreactors to obtain increased cell density. Cells are immobilized by forming alginate beads containing cells and gelatin particles, and dissolving the gelatin by heating to form cavities in the beads entrapping the cells. In a growth chamber of an airlift bioreactor, introduced oxygen-containing gas circulates growth medium in contact with the beads resulting in oxygen transfer to cells in the cavities of the beads where growth of the cells occurs. Preferably, bead formation is carried out in the growth chamber by dripping an alginate-cell gelatin suspension into a calcium solution contained in the growth chamber. Growth medium is then supplied to the chamber, and oxygen-containing gas is introduced to result in circulation of the growth medium and growth of the cells.

Abstract: Lactic acid produced by cells in culture is detected and used in a bioassay to determine cell growth and vitality. Lactic acid is detected by coupling the lactate dehydrogenase conversion of lactic acid to pyruvic acid to a reaction using micotinamide adenine dinucleotide in reduced form (NADH) to reduce a tetrazolium dye. The process can be used to serve as a bioassay for measuring biologically active compounds, particularly lymphokines.

Abstract: The disclosure provides an improved reactor/fermentor apparatus useful for carrying out cell culture and fermentation. The apparatus utilizes novel design features to provide optimum agitation of the cells while minimizing mechanical shear force. The reactor is composed of two chambers; an upper, wider chamber and a lower, small diameter chamber which are connected by inwardly sloping side walls. Agitation is accomplished by utilizing a gently flowing centrally disposed gas stream.

Abstract: A rapid cytopathic effect inhibition assay for interferon is disclosed. The assay can be completed in about 16 hours or less, allowing its use to assist in clinical diagnosis of viral infections and also, in monitoring the production and purification of interferon whether leukocyte or fibroblast.