Procedures for preparing biologically inactive, but immunogenic HIV-1 Tat protein (Tat toxoid) for human use.

Extracellular Tat can exercise its deleterious effects on cells surrounding HIV-1-infected cells and allow spreading of virus. Extracellular Tat should be neutralized by anti-Tat vaccination using as an immunogen a functionally inactivated but immunogenic Tat preparation (Tat toxoid). In the present paper we show that native Tat can be inactivated without impairment of its immunogenicity by subjecting it to various chemical treatments. Since the carboxyamidation reaction can be easily monitored and the carboxyamidated Tat retained the whole immunogenicity of the native molecule, it should be the toxoid of choice for mass immunization.