Human Immunodeficiency Virus 2, strain NIH-Z (HIV-2). Family: Retroviridae, genus: Lentivirus. Single-stranded, positive-sense enveloped RNA virus.

Lab adapted strain; grows well in transformed T-cell lines. HIV-2 causes disease similar to HIV-1 but is not as aggressive. Many people have been found infected with this virus without exhibiting overt disease. It is very similar to the related monkey virus SIV-2. Purified virus is a preparation made from clarified, virus infected tissue culture harvest fluids that are concentrated and cleaned of debris by a combination of ultracentrifugation, ultrafiltration and selection of viral band from a sucrose density gradient. This preparation contains live virus.