Infectious Virus Tracking by Fluorescent Live Cell Imaging in Primary Cells.

To successfully infect a cell, HIV-1 has to overcome several host barriers while exploiting cellular cofactors. HIV-1 infection is highly inefficient with the great majority of viral particles not being able to successfully integrate into the target cell genome. Nonproductive HIV-1 particles are degraded or accumulated in cellular compartments. Thus, it becomes hard to distinguish between viral behaviors that lead to effectively infecting the cell from the ones that do not by using traditional methods. Here, we describe the infectious virus tracking method that detects and quantifies individual fluorescent viral particles over time and links viral particle behavior to its infectivity. This method employs live-cell imaging at ultra-low MOIs to detect the outcome of infection for every HIV-1 particle.