Adhesion and fusion efficiencies of human immunodeficiency virus type 1 (HIV-1) surface proteins

Abstract

In about half of patients infected with HIV-1 subtype B, viral populations shift from utilizing the transmembrane protein CCR5 to CXCR4, as well as or instead of CCR5, during late stage progression of the disease. How the relative adhesion efficiency and fusion competency of the viral Env proteins relate to infection during this transition is not well understood. Using a virus-cell fusion assay and live-cell single-molecule force spectroscopy, we compare the entry competency of viral clones to tensile strengths of the individual Env-receptor bonds of Env proteins obtained from a HIV-1 infected patient prior to and during coreceptor switching. The results suggest that the genetic determinants of viral entry were predominantly enriched in the C3, HR1 and CD regions rather than V3. Env proteins can better mediate entry into cells after coreceptor switch; this effective entry capacity does not correlate with the bond strengths between viral Env and cellular receptors.

Advances in biosensing strategies for HIV-1 detection, diagnosis, and therapeutic monitoring

“…Cantilever sensors can also be used to differentiate between fusion and binding events of viral particles and living cells. For example, a single-molecule force spectroscope (SMFS) was employed to monitor the strength and lifetime of molecular bonds with a single-molecule resolution [97]. In this study, viruses were first immobilized on a cantilever surface of an atomic force microscope (AFM) and then operated in contact mode with a living cell (Fig.…”

“…Overall, cantilever sensor-based approaches can provide new insights of cellular mechanisms by monitoring mechanical responses to biochemical interactions and also be potentially used to detect ultralow concentrations of biomarkers, making these sensors and assays an ideal candidate for use in the POC diagnostic settings [97,98]. …”

“…The cantilever surface was functionalized with whole viruses to contact with cell surfaces expressing viral surface receptors. Displacement values of the cantilever were recorded to monitor molecular interactions [97]. (C) A quartz crystal microbalance surface was decorated with molecularly imprinting polymer to mimic biomolecular confirmation of gp41 epitope of HIV-1.…”

Microscopie à force atomique pour l’étude du cycle viral

“…En couplant cette information avec le balayage de la pointe, on obtient une cartographie de l'affinité pointeéchantillon ( Figure 3A) : c'est ce que l'on appelle la spectroscopie dynamique de force AFM [19][20][21]. Par exemple, en fixant sur la pointe de l'AFM des protéines virales d'enveloppe du VIH-1, la spectroscopie de force AFM permet une mesure localisée des interactions de ces protéines virales avec les récepteurs pré-sents dans la membrane externe d'une cellule immobilisée sur une surface [22], mimant ainsi l'interaction virus-cellule ( Figure 3B). .…”

“…Le temps nécessaire à la libération de la protéine par le récepteur, mesuré en observant temporellement le signal pour une force de retrait du levier donnée ( Figure 3B), permet la détermination de la constante cinétique de désorption. Cette dernière mesure a été réalisée par l'équipe de Wirtz [22] pour le virus VIH-1 lié à son récepteur cellulaire CD4 et aux corécepteurs CCR5 et CXCR4.…”