Lcm. Kaptein et al., OPTIMIZED CONDITIONS FOR THE PRODUCTION OF RECOMBINANT AMPHOTROPIC RETROVIRAL VECTOR PREPARATIONS, Gene therapy, 4(2), 1997, pp. 172-176
The production and stability of recombinant retroviral vectors was exa
mined at various temperatures. The two studied recombinant retroviral
vectors, based on different packaging cell lines, exhibited a four-fol
d increased half-life at 32 degrees C as compared to 37 degrees C. Sur
prisingly this increased stability, at 32 degrees C was only observed
within a very narrow temperature window. At 30 degrees C and 34 degree
s C, retroviral vector half-lives were quite similar to that at 37 deg
rees C. Regardless of the vector half-life, retroviral vectors accumul
ated in the culture medium for a period of 48 h before an equilibrium
was reached between retroviral vector production and decay. Maximal ac
cumulated recombinant retroviral titers were five- to ten-fold increas
ed after a medium incubation, at 32 degrees C as compared to 37 degree
s C. Furthermore, multiple cycles of freezing and thawing of retrovira
l vector supernatants hardly affected the recombinant retroviral vecto
r titer, independent of the presence of serum. This knowledge on chara
cteristics of recombinant retroviral vectors has practical implication
s for the manufacturing of these viruses for clinical gene therapy pro
tocols.