Journal of Research in Medical Sciences1735-199512520071016Designing a non-virulent HIV-1 strain: potential implications for vaccine227234ENAbbasRezaeiRezvanZabihollahi. rezvan_z_m@yahoo.comMansoorSalehiShararehMoghimHasanTamizifarNasrinYazdanpanahiGildaAmini200612152007082320070906BACKGROUND: Culturing and working with wild type HIV virions may produce contamination and infection. The main objective of this study was to design a non-infective HIV-1 strain that can be used safely in research laboratories for various research topics on HIV life cycle and pathogenesis. METHODS: Non-infective HIV-1 strain (mzNL4-3) was designed by deleting a 2 Kb sequence of HIV-1 (NL4-3 strain) genome that codes reverse transcriptase (RT) and integrase (IN) enzymes. RESULTS: The deletion removed 95% of RT and 34% of IN peptide sequences and abolished the functions of these enzymes totally. This deletion didn’t produce any other alteration in HIV genome, not only in mRNA level but also in transcription or translation levels. We named this strain, mutated z NL4-3 (mzNL4-3). CONCLUSIONS: Our mutated HIV-1 virions can be produced by transforming any mammalian cell line with mzNL4-3 vector (pmzNL4-3) but these virions can not replicate in any competent target cell. Hence, it can be used for many of the HIV-1 researches in a level 2 lab. mzNL4-3 has also the major antigen markers of HIV-1, NY5 and LAV strains, which are the most common strains of HIV-1. Therefore, mzNL4-3 can also be considered as a choice for HIV-1 vaccine investigation. Probably mzNL4-3 could be used for lab research and vaccine investigation. KEYWORDS: HIV-1, mzNL4-3, non-infectious, mutant, safe research, vaccine.