Effects of human recombinant alpha and gamma and of highly purified natural beta interferons on simian Spumavirinae prototype (simian foamy virus 1) multiplication in human cells.

The present study demonstrates the inhibitory effect of human recombinant interferons (r-Hu-IFN) alpha and gamma, and that of highly purified natural human interferon beta on the replication of simian foamy virus type 1 (SFV1) in human AV3-cell cultures. All IFN led to strong inhibition of the SFV1 cytopathic effect. Electron microscopy showed a 70 to 95% decrease in viral particles. Significant inhibition of virus-associated reverse transcriptase activity was found in supernatant fluids of infected IFN-treated cultures. Metabolic labelling of the virus confirmed the inhibition of extracellular release of SFV1. PAGE analysis of immunoprecipitates indicated a reduction in viral-specific protein bands. Altogether, these results indicate that the mechanism of inhibition of Spumavirinae infection by interferon differs from that described for the other Retroviridae, and particularly for types B, C and D viruses. Our data is of therapeutic interest since Spumavirinae have been linked to pathological processes such as de Quervain thyroiditis.