[Inhibition of the production of infectious particles in cells infected with Junín virus in the presence of tunicamycin].

The antibiotic tunicamycin, an inhibitor of glycoprotein synthesis, suppressed Junin virus multiplication in Vero cells. No infectious virus was formed if tunicamycin was added, at a concentration of 1 microgram/ml, immediately after virus adsorption and remained up to the end of the replicative cycle. Tunicamycin added at 24,48 or 72 hours p.i. immediately stopped virus synthesis. The effect was irreversible. Virus grown in the presence or absence of tunicamycin and labelled with 3H-uridine was purified and layered on a (20-60%) sucrose gradient. The radioactive profile of both gradients was coincident. The total number of cpm associated to the peak gradient of virus grown with tunicamycin represented 70% of the cpm from control virus. Since viral infectivity was 99.4% inhibited in the presence of TM it can be assumed that most of the radioactive particles formed are not infectious. Therefore, in the presence of tunicamycin Junin virus buds normally. From these results we can conclude that carbohydrates are important for viral infectivity but play no role in the transport of viral proteins through cellular membranes.