The interaction of Mengo virus ribonucleic acid with L, HeLa and human diploid cells: a comparative study

A study, designed to define the optimal conditions for infecting L, HeLa and human diploid cells with Mengo RNA, showed that the three cell types differ with respect to (a) the concentration of sucrose (in PBS) that produces maximum stimulation of infectious center (I.C.) formation (0.6 M, 1.2 M and 1.0 M for L, HeLa and human diploid cells respectively) and (b) the optimal combination of sucrose and dimethyl-sulfoxide (DMSO). With all three cell types, diethylaminoethyldextran (DEAE-D) was found to produce maximum stimulation of I.C. formation when present, in PBS, at a concentration of 100 μg/ml. Direct comparisons of I.C. formation in the three cell types using the sucrose, sucrose-DMSO and PBS-DEAE-D media optimal for each revealed that (a) the best medium for titration in L and HeLa cells is PBS containing 100 μg DEAE-D/ml, (b) DMSO produces a 4–8 fold increase in I. C. formation in L cells, but is only marginally effective in HeLa cells, and (c) the optimal medium for titration in human diploid cells is sucrose-DMSO. The results of studies of the “uptake” of ³H-Mengo RNA showed that there is no correlation between the amount of RNA that becomes cell associated and the number of I.C.'s that are produced in the cell population.