title: High sensitivity detection and sorting of infectious human immunodeficiency virus (HIV-1) particles by flow virometry.
abstract: Detection of viruses by flow cytometry is complicated by their small size. Here, we characterized the ability of a standard (FACSAria II) and a sub-micron flow cytometer (A50 Micro) to resolve HIV-1 viruses. The A50 was superior at resolving small particles but did not reliably distinguish HIV-1, extracellular vesicles, and laser noise by light scatter properties alone. However, single fluorescent HIV-1 particles could readily be detected by both cytometers. Fluorescent particles were sorted and retained infectivity, permitting further exploration of the functional consequences of HIV-1 heterogeneity. Finally, flow cytometry had a limit of detection of 80 viruses/ml, nearly equal to PCR assays. These studies demonstrate the power of flow cytometry to detect and sort viral particles and provide a critical toolkit to validate methods to label wild-type HIV-1; quantitatively assess integrity and aggregation of viruses and virus-based therapeutics; and efficiently screen drugs inhibiting viral assembly and release.
authors.affiliation: Center for Proteomics and Bioinformatics, Department of Nutrition, School of Medicine, Case Western Reserve University, Cleveland OH 44106, USA.
authors.forename: Michał M
authors.initials: MM
authors.lastname: Bonar
authors.affiliation: Center for Proteomics and Bioinformatics, Department of Nutrition, School of Medicine, Case Western Reserve University, Cleveland OH 44106, USA. Electronic address: john.c.tilton@case.edu.
authors.forename: John C
authors.initials: JC
authors.lastname: Tilton
mesh_terms: D015496:CD4-Positive T-Lymphocytes / Q000821:virology; D002478:Cells, Cultured; D000067128:Extracellular Vesicles / Q000502:physiology; D005434:Flow Cytometry / Q000379:methods*; D005453:Fluorescence; D015497:HIV-1 / Q000302:isolation & purification*; D006801:Humans; D057230:Limit of Detection; D014771:Virion / Q000302:isolation & purification*
keywords: Extracellular vesicles; Flow cytometry; Flow virometry; HIV; Quantification; Virus sorting