Enhancement of infectivity of encephalomyocarditis virus RNA by amphotericin B methyl ester

Modification of membrane permeability by animal viruses

Animal viruses modify membrane permeability during lytic infection. There is a co-entry of macromolecules and virion particules during virus penetration and a drastic change in transport and membrane permeability at the late stages of the lytic cycle. Both events are of importance to understand different molecular aspects of viral infection, as virus entry into the cell and the interference of virus infection with cellular metabolism. Other methods of cell permeabilization of potential relevance to understand the mechanism of viral damage of the membrane are also discussed.

Effect of deoxycholate, amphotericin B and fongizone on transmissible gastroenteritis coronavirus

At a concentration of 2 μg/ml, neither amphotericin B nor deoxycholate had an inactivating effect upon transmissible gastroenteritis Coronavirus in-fectivity. However, amphothericin B stimulated plaque formatin in agarose and facilitated the entry of viral RNA into swine testis cells. The combination of amphotericin B + deoxycholate inactivated virus infectivity and induced a decrease in plaque diameter. Finally, in the presence of these agents, the production of infectious virus and interferon was unchanged.

Effects of amphotericin B on hepatitis B virus

We investigated the effects of amphotericin B (AmB) on the ultrastructure and biochemistry of hepatitis B virus (HBV) and hepatitis B surface antigen (HBsAg) particles. These effects were compared with those reported for AmB and other polyene antibiotics on other lipid-enveloped viruses and artificial membranes. Treatment of HBV particles with concentrations of AmB ranging from 5 to 250 microgram/ml resulted in (i) an increase in HBV deoxyribonucleic acid polymerase activity as the concentration of Amb increased; (ii) changes in the electron microscopic appearance of HBV ranging from increased penetration of negative stain into the lipid envelope to disruption of the virus; and (iii) an increase in density form 1.165 to 1.225 g/ml. In addition, AmB treatment of HBsAg particles resulted in disruption into a nonparticulate HBsAg-reactive fraction and an HBsAg-AmB complex fraction with no HBsAg immunoreactivity.

Enhancement of viral RNA-induced interferon production of L cells treated with insulin and amphotericin B methyl ester

A study was initiated to develop a more efficient method of producing high-titered L cell interferon. The induction of interferon by viral infectious RNA could be augmented by pretreating the cell cultures with insulin and infecting in the presence of Amphotericin B methyl ester (AmBME). L cells were treated for 24 hr with different concentrations of insulin and then challenged with MM virus RNA suspended in a balanced salt solution with and without AmBME. The fluids were collected 48 hr after infection and assayed for interferon activity. Interferon production was markedly increased in insulin-treated cultures and that the increase was dose-dependent.