Human Immunodeficiency Virus 1, strain IIIB (HIV-1). Family: Retroviridae, genus: Lentivirus. Single-stranded, positive-sense enveloped RNA virus. Direct pelleted virus concentrated 1000X from clarified tissue culture supernatant without further purification. This preparation contains live virus. IIIB is one of the original HIV-1 isolates; it is a group M lab-adapted virus and grows very well in transformed T-cell lines. It utilizes the CXCR4 receptor. HIV-1IIIB direct pelleted virus is generally more infectious than HIV-1IIIB purified virus (Cat. No. 10-118-000).