For in vitro use (cell culture studies), is viral purification required?
No. If viruses will be used in in vitro cell cultures, double CsCl purification is not required. For in vivo studies (i.e. animal studies), purification is essential in order to remove defective particles, cell debris, and small amounts of media components, since these contaminants induce significant immune responses. In addition, CsCl purification will concentrate the virus to a level suitable for in vivo injections.
