EFFECTS OF METHOCEL-A15LV, POLYETHYLENE-GLYCOL, AND PORYVINYL ALCOHOLON CD13 AND CD33 RECEPTOR SURFACE CONTENT AND METABOLISM OF HL60 CELLS CULTURED IN STIRRED-TANK BIOREACTORS

Flow cytometry was used to examine the effect of hydrodynamic forces i n a stirred tank bioreactor on the CD13 and CD33 receptor surface cont ent of HL60 (human promyelocytic leukemia) cells. A step increase in a gitation rate from 80 to 400 rpm reduced the HL60 cell apparent growth rate and increased the CD13 receptor surface content per cell, on ave rage, by 95%. In contrast, this step increase in agitation rate to 400 rpm decreased the CD33 receptor surface content per cell, on average, by 10%. The protective effects of 0.1% Methocel A15LV, polyethylene g lycol (PEG), and polyvinyl alcohol (PVA) on CD13 and CD33 receptor sur face content were examined under agitation at 300 rpm in parallel 2 L bioreactor runs. The average CD33 receptor surface content was unaffec ted by the presence of Methocel A15LV or PEG, while PVA had a slight p rotective effect. In contrast, in terms of CD13 receptor content, HL60 cells agitated at 300 rpm with Methocel A15LV, PEG, or PVA behaved li ke cells agitated at 80 rpm with no media additives (McDowell and Papo utsakis, 1998). That is, Methocel A15LV, PEG, and PVA prevented the tr ansduction of mechanical forces which affect CD13 cell content. HL60 c ells cultured with 0.1% A15LV, PEG or PVA under conditions of mild agi tation (60 rpm) in spinner flasks exhibited glucose consumption and la ctate production rates that were approximately 20% lower than values o f cultures containing no additive. Under conditions of agitation at 30 0 rpm in the 2 L bioreactor, the presence of A15LV, PEG, and PVA reduc ed the HL60 glucose consumption and lactate production rates by approx imately 50%. Thus, media additives can dramatically reduce lactate acc umulation in agitated bioreactors due to cell growth, in addition to p roviding protection from cellular injury. (C) 1998 John Wiley & Sons, Inc.