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dc.contributor.authorRay, K.
dc.contributor.authorMengistu, M.
dc.contributor.authorOrlandi, C.
dc.contributor.authorPazgier, M.
dc.contributor.authorLewis, G.K.
dc.contributor.authorDeVico, A.L.
dc.date.accessioned2019-08-16T13:45:21Z
dc.date.available2019-08-16T13:45:21Z
dc.date.issued2019
dc.identifier.urihttps://www.scopus.com/inward/record.uri?eid=2-s2.0-85069476486&doi=10.3389%2ffimmu.2019.01512&partnerID=40&md5=f3bdb2cb4e4f9148d58cdf8cb62df963
dc.identifier.urihttp://hdl.handle.net/10713/10344
dc.description.abstractThe trimeric envelope spikes on the HIV-1 virus surface initiate infection and comprise key targets for antiviral humoral responses. Circulating virions variably present intact envelope spikes, which react with neutralizing antibodies; and altered envelope structures, which bind non-neutralizing antibodies. Once bound, either type of antibody can enable humoral effector mechanisms with the potential to control HIV-1 infection in vivo. However, it is not clear how the presentation of neutralizing vs. non-neutralizing epitopes defines distinct virus populations and/or envelope structures on single particles. Here we used single-virion fluorescence correlation spectroscopy (FCS), fluorescence resonance energy transfer (FRET), and two-color coincidence FCS approaches to examine whether neutralizing and non-neutralizing antibodies are presented by the same envelope structure. Given the spatial requirements for donor-acceptor energy transfer (≤10 nm), FRET signals generated by paired neutralizing and non-neutralizing fluorescent Fabs should occur via proximal binding to the same target antigen. Fluorescent-labeled Fabs of the neutralizing anti-gp120 antibodies 2G12 and b12 were combined with Fabs of the non-neutralizing anti-gp41 antibody F240, previously thought to mainly bind gp41 "stumps." We find that both 2G12-F240 and/or b12-F240 Fab combinations generate FRET signals on multiple types of virions in solution. FRET efficiencies position the neutralizing and non-neutralizing epitopes between 7.1 and 7.8 nm apart; potentially fitting within the spatial dimensions of a single trimer-derived structure. Further, the frequency of FRET detection suggests that at least one of such structures occurs on the majority of particles in a virus population. Thus, there is frequent, overlapping presentation of non-neutralizing and neutralizing epitope on freely circulating HIV-1 surfaces. Such information provides a broader perspective of how anti-HIV humoral immunity interfaces with circulating virions. Copyright 2019 Ray, Mengistu, Orlandi, Pazgier, Lewis and DeVico.en_US
dc.description.sponsorshipResearch reported in this publication was supported by the National Institute of General Medical Sciences and National Institute of Allergy and Infectious Diseases, of the National Institutes of Health under Award Numbers (R01 GM117836 and R01 GM117836-S1 to KR) and (P01 AI120756 to AD). The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health.en_US
dc.description.urihttps://www.doi.org/10.3389/fimmu.2019.01512en_US
dc.language.isoen-USen_US
dc.publisherFrontiers Media S.A.en_US
dc.relation.ispartofFrontiers in Immunology
dc.subjectEpitope exposureen_US
dc.subjectFRET-FCSen_US
dc.subjectNeutralizing and non-neutralizing epitopesen_US
dc.subjectSingle HIV-1 virionen_US
dc.subjectTwo-color coincidence fluorescence correlation spectroscopy (FCS)en_US
dc.titleConcurrent Exposure of Neutralizing and Non-neutralizing Epitopes on a Single HIV-1 Envelope Structureen_US
dc.typeArticleen_US
dc.identifier.doi10.3389/fimmu.2019.01512


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