This technology includes a method to facilitate identification of drug targets that can prevent SARS-related viruses from entering human cells with ACE2 receptors on the plasma membrane. Surface binding to cellular ACE2 of the SARS-CoV-2 virus is the first step of infection for the disease COVID-19. The invention allows for visualization of cell binding and entry of a “quantum dot conjugated virus spike protein” (hereafter referred to as either a ‘QD-Spike conjugate’ or a ‘pseudo-virion’) and can be used to screen libraries of drugs that prevent/inhibit this cell entry. The QD-Spike conjugates can be visualized in real time using high-content microscopy in live assays of human cells treated with both QD-Spike and drug targets.
To date, there is no assay that can report on the binding of Spike to ACE2 on the cell surface, nor is there an assay that can report on the endocytosis of ACE2 in living cells without the need for complicated immunostaining procedures in a BSL-2 facility. The QD pseudo-virion mimics the shape and physiological activity of a SARS virus particle without being infectious or hazardous to humans.