Complete and repeatable inactivation of HIV-1 viral particles in suspension using a photo-labeled non-nucleoside reverse transcriptase inhibitor

Abstract

A method is described for achieving repeatable, complete inactivation of HIV, based on photo-inactivation of HIV reverse transcriptase (RT) with a non-nucleoside reverse transcriptase inhibitor (NNRTI), photoactive 4-[[4-[(4-azido-2,6-dimethylphenyl) amino]-2-pyrimidinyl]amino]benzonitrile (PA-DAPYa). These results show that PA-DAPYa inactivated completely a suspension of cell-free HIV-1 viral particles in a dose and time-dependent manner. Using an ELISA assay for p24, it is demonstrated that a 500nM concentration of PA-DAPYa is able to inactivate 500 TCID50 of HIV viral particles in suspension when irradiated with non-microbicidal wavelength UV light for 30min. No active p24 was detected on days 7, 14, and 21 days after culturing the inactivated HIV in peripheral blood mononuclear cells (PBMCs). Several batches of large quantities of HIV viral particles were demonstrated to be inactivated completely and repeatedly by this method. Therefore, a reliable method has been developed to inactivate HIV viral particles in a reproducible manner using an optimal concentration of PA-DAPYa and duration of UV exposure time of the treated particles. The inactivation of viral particles in suspension allows for large-scale production of an injectable formulation of inactivated HIV viral particles for vaccine development which should preserve the conformational and antigenic integrity of viral surface proteins.