Differential N- and O-glycosylation signatures of HIV-1 Gag virus-like particles and coproduced extracellular vesicles.

Human immunodeficiency virus 1 (HIV-1) virus-like particles (VLPs) are nanostructures derived from the self-assembly and cell budding of Gag polyprotein. Mimicking the native structure of the virus and being noninfectious, they represent promising candidates for the development of new vaccines as they elicit a strong immune response. In addition to this, the bounding membrane can be functionalized with exogenous antigens to target different diseases. Protein glycosylation depends strictly on the production platform and expression system used and the displayed glycosylation patterns may influence downstream processing as well as the immune response. One of the main challenges for the development of Gag VLP production bioprocess is the separation of VLPs and coproduced extracellular vesicles (EVs). In this study, porous graphitized carbon separation method coupled with mass spectrometry was used to characterize the N- and O- glycosylation profiles of Gag VLPs produced in HEK293 cells. We identified differential glycan signatures between VLPs and EVs that could pave the way for further separation and purification strategies to optimize downstream processing and move forward in VLP-based vaccine production technology.