   sv40 is an abbreviation for simian vacuolating virus 40 or simian virus 40, a polyomavirus that is found in both monkeys and humans. it was named for the effect it produced on infected green monkey cells, which developed an unusual number of vacuoles. like other polyomaviruses, sv40 is a dna virus that has the potential to cause tumors, but most often persists as a latent infection. sv-40 discovery revealed that between 1955 and 1963 around 90% of children and 60% of adults in usa were inoculated with sv40-contaminated poliovirus vaccines. ==history== the sv40 was first identified by ben sweet and maurice hilleman in 1960 when they found that between 10-30% of the poliovirus vaccines in the usa were contaminated with sv-40. in 1962, bernice e. eddy described the sv40 oncogenic function inducing sarcoma and ependymomas in hamsters inoculated with monkeys cells infected with sv40. the complete viral genome was sequenced by walter fiers and his team at the university of ghent (belgium) in 1978. ==virology== sv40 consists of an unenveloped icosahedral virion with a closed circular dsdna genome of 5kb. the virion adheres to cell surface receptors of mhc class 1 by the virion glycoprotein vp1. penetration into the cell is through a caveolin vesicle. inside the cell nucleus, the cellular rna polymerase ii acts to promote early gene expression. this results in an mrna that is spliced into two segments. the small and large t antigens result from this. the large t antigen has two functions: 5% will go 
Polyomaviruses Vaccine_controversies