Etiology and Pathogenesis > Simian Virus 40

Meeting Abstract

SV40 vertical transmission and pathogenesis in Syrian Golden hamsters

Amy S. Arrington, Connie Wong, Regis A. Vilchez, Janet S. Butel

Baylor College of Medicine, Houston, TX.

SV40 is a known tumor virus. 
Malignancies induced by SV40 in hamsters are synonymous to those found associated with SV40 DNA in human tumors. 
Some of these tumors occur in infants, particularly ependymomas and choroid plexus tumors. 
Our laboratory showed SV40 sequences and T-antigen expression in pediatric brain cancers and the isolation of infectious virus from a primary pediatric brain tumor. 
This raises the question of how the virus is transmitted in the human population. 
The goals of this project were to investigate the occurrence of vertical transmission of SV40 and to examine short and long-term pathogenic effects in vivo. 
To address these aims, a model was developed using Syrian Golden hamsters. 
Pregnant dams were inoculated with isolates of SV40 by intraperitoneal inoculation mid-gestation. 
Offspring of inoculated dams were sacrificed 7 days post-parturition and analyzed by histology and for the presence of SV40 by PCR. 
To observe for physiological effects of SV40, litters were held up to 7 months. 
Results suggest a 30% to 60% transmission rate from mother to fetus in hamsters inoculated with SV40. 
PCR analysis detected viral DNA in different organs, including brain, spleen, liver, kidney, and lung. 
Histological analyses support these data, showing multifocal syncytia, polykaryosis and fibrosis in the lungs, and multifocal nephropathy and mild syncytia in the kidneys of ill animals. 
To investigate if transplacental transmission of SV40 occurs in utero, pregnant dams were inoculated mid-gestation and sacrificed on day 17 of an 18-day gestation period. 
Maternal tissues (organs, sera, placenta) were harvested separately from fetuses. 
DNA was extracted from tissues and tested for viral DNA by PCR. 
Results suggest that both maternal and fetal tissues were positive for SV40, as 30-45% of fetuses tested by PCR were positive for virus, supporting intrauterine infection by SV40 in Syrian hamsters. 
This is the first report of vertical transmission of SV40 and suggests that mother-to-child transmission of SV40 may be a possible route of viral spread in humans.

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