Method of producing infectious reovirus

DETAILED DESCRIPTION OF THE INVENTION The present invention is directed to a method of producing mammalian reovirus by using human embryo kidney 293 (HEK 293) cells.
We found that HEK 293 cell are a more efficient host cell for reovirus than L-929 cells or Vero cells.
Although never reported to support reovirus replication before, HEK 293 cells produced more reovirus in a shorter time course than L-929 cells or Vero cells.
Consequently, by using HEK 293, production costs can be lowered.
Moreover, because the reovirus is still associated with HEK 293 cells when the titer is sufficiently high, a relatively simple procedure may be used to purify the virus and further lower the production cost.
Prior to describing the invention in further detail, the terms used in this application are defined as follows unless otherwise indicated.
Definitions As used herein, "HEK 293 cells" refer to the human embryo kidney cell line designated 293 (ATCC Number CRL-1573) or its derivatives.
For example, 293/SF cells (ATCC Number CRL-1573.
1) are HEK 293 cells which have been adapted to grow in serum-free media.
Also contemplated in this invention are HEK 293 cells adapted to grow in other culture conditions, or any kind of HEK 293 cells or derivatives which are transformed with an exogenous DNA, provided that this transformation does not impair the ability of the cells to support efficient reovirus production as described in this invention.
As used herein, "reovirus" refers to any virus classified in the reovirus genus, whether naturally occurring, modified or recombinant.
Reoviruses are viruses with a double-stranded, segmented RNA genome.
The virions measure 60 80 nm in diameter and possess two concentric capsid shells, each of which is icosahedral.
The genome consists of double-stranded RNA in 10 12 discrete segments with a total genome size of 16 27 kbp.
The individual RNA segments vary in size.
Three distinct but related types of reovirus have been recovered from many species.
All three types share a common complement-fixing antigen