Comparison of two kinds of methods to determine the titer of recombinant retrovirus containing beta-globin gene based on G418 selection.

Four recombinant retrovirus (RV) vectors containing human beta-globin gene and regulatory elements were constructed. To determine the titers of recombinant RV from corresponding producer cell lines, we compared two kinds of method (the simple and the conventional) based on G418 resistance, which is conferred by neo gene of RV vector. The results demonstrated that the simple method shortened the selection period to 3 d instead of 10-12 d with the conventional method and reduced the amount of work; importantly, the titers determined by the simple method were not different significantly from those measured by the conventional method. It can be concluded that the simple method can be used to determine the titers of recombinant RV containing not only cDNA but also genomic DNA with introns and complex regulatory elements instead of the conventional method.