Identification of the major immunogenic structural proteins of human foamy virus.

We have identified the major immunogenic structural proteins of the human foamy virus (HFV), a distinct member of the foamy virus subfamily of Retroviridae. Radiolabelled viral proteins were immunoprecipitated from HFV-infected cells by foamy virus antisera of human and non-human primate origin. Precipitated viral proteins were in the range of 31K to 170K. Labelling of proteins with [14C]glucosamine or with [35S]methionine in the presence of tunicamycin, as well as endo-beta-N-acetylglycosaminidase H and F treatment of [35S]methionine-labelled proteins, revealed three viral glycoproteins of approximately 170K, 130K and 47K, most likely representing the env gene-encoded precursor, the surface glycoprotein and the transmembrane protein of HFV, respectively.

Epidemiological studies of bovine spumavirus.

Bovine spumavirus (BSV) infection is shown to be endemic in some herds in north Queensland. The virus was readily isolated from leucocytes of the majority of mature cattle which were BSV antibody positive (BSV reactors) in the agar gel precipitin test (AGPT). Calves born to dams which were BSV reactors showed no BSV antibody or circulatory leucocyte-associated BSV (CLAB) at birth, but became BSV reactors following ingestion of colostrum, and maintained such evidence of passive immunity until 3-5 months of age. Experimental infection of dams with BSV at 5-7 months of gestation did not cause foetal infection. In groups of young animals at pasture, segregated by age and sex, no evidence of BSV infection occurred, following loss of passive immunity, until 18-24 months of age. At this time, occasional members of some groups (both male and female) became BSV reactors and showed CLAB. At approximately 24 months old, following mixing in groups with older cows, and single-sire mating, 34% of heifers became BSV reactors within 10 weeks. A herd survey indicated 85% of 2-3-year-old cows to be BSV reactors; thereafter, the percentage of reactors declined gradually with increasing age. Using BSV grown in cell culture, transmission of infection by throat spray was the most successful route, 7 of 7 (100%) of susceptible cattle becoming BSV reactors within 8 weeks of spraying. Using the intravenous route, only 2 of 5 (40%) susceptible cattle became BSV reactors, and swabbing of cell culture virus into the prepuce or vagina did not result in infection of 4 BSV-susceptible animals.(ABSTRACT TRUNCATED AT 250 WORDS)

Purification and characterization of the major envelope glycoprotein of simian foamy virus type 1.

Simian foamy virus type 1 (SFV-1), the prototype of the Spumavirinae, was subjected to disruption and serial purification procedures. Separation of SFV-1 envelope components from viral cores was verified by electron microscopy, density gradient centrifugation and polyacrylamide gel electrophoresis. After affinity chromatography of the envelope polypeptides on a concanavalin A-Sepharose column, a highly purified 70 000 mol. wt. protein was recovered. Glycosylation of this gp70 was confirmed by glucosamine labelling. Immunological studies with anti-SFV antisera confirmed the type-specificity of this envelope gp70.

The RNA of the human syncytium-forming (foamy) virus.

Human syncytium-forming (foamy) virus was labeled with 3H-uridine and banded isopycnically in sucrose gradients (buoyant density = 1.16 to 1.18 g/cm3). Viral RNA extracted from the banded virus was analyzed either by rate zonal separation in sucrose gradients or by polyacrylamide-agarose gel electrophoresis. The results indicated that purified HSFV contains a 60S RNA component plus several smaller molecular weight RNA components. On dissociation with heat, smaller RNA structures were released from the 60S component. These results indicate that the genome of HSFV, like the other members of the Retroviridae family, is composed of an aggregate of several RNA species.