The Chimpanzee SIV Envelope Trimer: Structure and Deployment as an HIV Vaccine Template

Andrabi, Raiees; Pallesen, Jesper; Allen, Joel D.; Song, Ge; Zhang, Jinsong; de Val, Natalia; Gegg, Gavin; Porter, Katelyn; Su, Ching-Yao; Pauthner, Matthias; Newman, Amanda; Bouton-Verville, Hilary; Garces, Fernando; Wilson, Ian A.; Crispin, Max; Hahn, Beatrice H.; Haynes, Barton F.; Verkoczy, Laurent; Ward, Andrew B.; Burton, Dennis R.

The binding experiments of Abs to the affinity purified trimers were performed with an Octet K2 system (ForteBio, Pall Life Sciences). Briefly, the mAbs or IgGs (10 ug/mL in PBST) were immobilizing onto hydrated anti-human IgG-Fc biosensors (AHC: ForteBio) for 60 s to achieve a binding response of at least 1.0. After Ab capture, the sensor was placed in a PBST wash buffer to remove the unbound Ab to establish a baseline signal. Next, the IgG immobilized sensor was dipped into a solution containing SOSIP.664 trimer protein as analyte and incubated for 120 s at 1000 rpm. Following this, the trimer bound to IgG immobilized sensor was removed from the analyte solution and placed into the PBST buffer for 240 s at 1000 rpm. The 2-and 4-minute binding intervals respectively denote the association and dissociation binding curves reported in this study. The sensograms were corrected with the blank reference and fit (1:1 binding kinetics model) with the ForteBio Data Analysis version.9 software using the global fitting function. The data are represented as maximum binding response or the association and dissociation curve fits.