Pc. Collins et al., REAL-TIME METHOD FOR DETERMINING THE COLONY-FORMING CELL CONTENT OF HUMAN HEMATOPOIETIC-CELL CULTURES, Biotechnology and bioengineering, 55(4), 1997, pp. 693-700
Glucose and lactate metabolic rates were evaluated for cultures of cor
d blood (CB) mononuclear cell (MNC), peripheral blood (PB) MNC, and PB
CD34(+) cell cultures carried out in spinner flasks and in T-flasks i
n both serum-containing and serum-free media. Specific glucose uptake
rates (q(gluc), in micromoles per cell per hour) and lactate generatio
n rates (q(lac)) correlated with the percentage of colony-forming cell
s (CFC) present in the culture for a broad range of culture conditions
. Specifically, the time of maximum CFC percentage in each culture coi
ncided with the time of maximum q(gluc) and q(lac) in cultures with di
fferent seeding densities and cytokine combinations. A two-population
model (Q(lac) = alpha[CFC] + beta([TC] - [CFC]), where [TC] is total c
ell concentration; Q(lac) is volumetric lactate production rate in mic
romoles per milliliter per hour; alpha is q(lac) for an average CFC; a
nd beta is q(lac) for an average non-CFC) was developed to describe la
ctate production. The model described lactate production well for cult
ures carried out in both T-flasks and spinner flasks and inoculated wi
th either PB or CB MNC or PB CD34(+) cells. The values for alpha and b
eta that were derived from the model varied with both the inoculum den
sity and the cytokine combination. However, preliminary results indica
te that cultures carried out under the same conditions from different
samples with similar initial CD34(+) cell content have similar values
for alpha and beta. These findings suggest that it should be possible
to use lactate production data to predict the harvest time that corres
ponds to the maximum number of CFC in culture. The ability to harvest
ex vivo hematopoietic cultures for transplantation when CFC are at a m
aximum has the potential to speed the rate at which immunocompromised
patients recover. (C) 1997 John Wiley & Sons, Inc.