CCR5 knock-out is better than inhibition. Here is a link to an article on SGMO's elegant solution. <A HREF="http://phx.corporate-ir.net/phoenix.zhtml?c=120938&p=irol-newsArticle&t=Regular&id=909834&" target="_blank">http://phx.corporate-ir.net/phoenix.zhtml?c=120938&p=irol-newsArticle&t=Regular&id=90983...</A> Dave