Flowcytometric analysis of individual viral particles

Friday, November 08, 2013 — Poster Session IV
2:00 p.m. – 4:00 p.m.	FAES Academic Center (Upper-Level Terrace)	NICHD	VIROL-1

Authors

A Arakelyan
S Zicari
W Fitzgerald
E Zaitseva
JC Grivel

Abstract

Small viruses with a diameter of less than 200 nm are well outside the light scattering detection range of most commercial cytometers. Here, we report on a technology, which allows the detection and characterization of antigens on individual virions using multi-color flow cytometric analysis on commercial cytometers. The technology is based on capturing virions with magnetic nanoparticles (MNPs) coupled to antibodies specific for antigens present on the virion surface, staining virions with monoclonal antibodies, and separating the formed MNPs-virion complexes from unbound antibodies in a high gradient magnetic field. The stained complexes are then acquired on a flow cytometer set to trigger on fluorescence. We applied this technology to analyze antigenic makeup of HIV-1 and Dengue virus. Using HIV-specific-MNPs we studied the expression, on HIV-1 virions, of two cellular antigens, HLA-DR and LFA-1. We found that HIV virions produced in the same cell line are heterogeneous regarding their incorporation of these two markers. Also HIV virions produced in different cell types are different. Using Dengue-specific-MNPs carrying antibodies recognizing ubiquitous E-protein we characterized the furin-dependant maturation state of this virus. We found that the majority of Dengue viruses produced in a furin expressing cell line are immature.