Abstract: Objective Based on the chemical coupling method, the blood-derived human immunoglobulin-NK cell retargeting molecular conjugate was constructed and its antiviral effect was evaluated. Methods Using human immunoglobulin products with high anti-VZV antibody titers as raw materials, the conjugates of human immunoglobulin and NK cell redirection molecule (anti-CD16a scFv) with different coupling degrees, IgG×αCD16a, were prepared by Traut's reagent and Sulfo-SMCC. The conjugated products were characterized by non-reducing SDS-PAGE, and the binding ability of IgG×αCD16a to effector cells (NK cells) was determined by flow cytometry. ADCC activity was detected by LDH release assay, the release of cell killing mediators (granzyme B, perforin) and cytokines (TNF-α, IFN-γ) was detected by ELISA. The killing ability of coupled product IgG×αCD16a and unconjugated human immunoglobulin on VZV infected cells was systematically evaluated. Results The coupling rate of IgG×αCD16a can reach more than 30%. IgG×αCD16a can bind to NK cells, and the binding ratio is higher than that of unconjugated human immunoglobulin. Compared with unconjugated human immunoglobulin, IgG×αCD16a significantly enhanced the ADCC activity on VZV infected cells and the release level of cytokines (TNF-α, IFN-γ). Conclusion The molecular chemical conjugate of blood-derived human immunoglobulin -NK cell redirection based on chemical coupling can effectively improve the antiviral effect of blood-derived human immunoglobulin, and provide a new idea for the development of a new generation of highly effective anti-viral antibody drugs.

Key words: Blood-derived human immunoglobulin, NK cells, Redirecting molecules, Chemical conjugation, Antiviral