Virus particle-based antibody-dependent cellular phagocytosis assay for HIV

IntroductionAntibodies mediate a wide range of antiviral functions, including neutralization and diverse Fc-dependent effector activities. Among these, antibody-dependent cellular phagocytosis (ADCP) has emerged as an important mechanism contributing to pathogen clearance, including during HIV-1 infection.

Conventional bead-based ADCP assays typically rely on recombinant envelope glycoprotein (Env), which offers practical advantages but fails to fully recapitulate the native structural, conformational, and glycan features of virion-associated Env. This limitation reduces the physiological relevance of these assays for evaluating antibody function in vivo.MethodsWe developed a virus particle-based ADCP assay designed to preserve the native membrane-embedded conformation and glycosylation of HIV-1 Env.

The assay uses sucrose-purified, inactivated HIV-1 virions coupled to fluorescent beads as phagocytic targets, and the THP-1 human monocytic cell line as effector cells. The assay was optimized for sensitivity, reproducibility, and high‑throughput compatibility, and was applied to evaluate ADCP responses mediated by both monoclonal and polyclonal antibodies across multiple species.ResultsThe virus particle-based ADCP assay enabled robust and reproducible measurement of antibody-mediated phagocytosis in a biologically relevant antigen format.