抄録
In an attempt to analyze the relationship between viral multiplication and the host cell metabolism, the effects of two metabolic inhibitors, that is, 5, 6-Dichlcro-1-β-D ribofuranosyl benzimidazole (DRB) and proflavine, upon one step growth cycle of ectromelia virus in L cell tissue cultures were studied. As the biological tests, infectivity (PFU), complement fixing antigen and the percentage of “B” type inclusions which proved to be the site of DNA and viral antigen were examined.
Morphological studies were also carried out on the inclusions. The dosage of 20γ/ml of DRB which is not toxic to cell reproduction for a certain period, could still suppress the formation of any of the three componeots mentioned above when administered 24 hours prior to virus infection. Inspite of the remarkable decrease in the number of inclusions, each inclusion formed developed, showing regularly granular and network structure just as the inclusions in untreated groups. However, DRB turned out almost ineffective when it was administered after the stage of virus synthesis. These results suggest that some disturbance of RNA metabolism in the host cell caused by DRB prior to the virus infection, might inhibit bit the synthesis of virus DNA and viral protein.
The dosage of 1mg or 2mg of RNase per ml. which does not affectt much the cell reproduction, was found to have a very similar effect on the viral multiplication to that of 20γ/ml of DRB.
The attitudes of these two substances concerning RNA metabolism towards the viral growth indicate that there might be an intimate relationship between the multiplication of DNA type virus and RNA metabolism in the host cells.
In the experiments with 0.5γ/ml of proflavine which does not affect the cell growth, only infectivity of virus was suppressed by both pre-and post treatment of virus inoculation. However, both complement fixing antigen titer and inclusion cell percentage were almost as high as those in the control. It may be of interest to note that the morphological development of inclusions formed was somewhat inhibited.
When more than 2.5γ/ml of proflavine which is destructive to the cell growth, was given at any stage after virus inoculation, infectivity was remarkably suppressed and most of the “B” type inclusions formed under this condition were small and compact, showing poor development of the inclusion bodies, in spite of the considerably high percentage of inclusion formation. However, all proflavine treated “B” type inclusions gave the same degree of Feulgen reaction and positive fluorescein antibody reaction as those of the control, showing the synthesis of these virus components. The “A” type inclusion (Marchal body) could hardly been observed by 16 hours.
These results seem to support the idea of De Mars that proflavine may interfare either with a hypothetical assembly mechanism or with the synthesis of some as yet unrecognized virus constituents.
