A Single-Step Chemoenzymatic Reaction for the Construction of Antibody-Cell Conjugates

Employing live cells as therapeutics is a direction of future drug discovery. An easy and robust method to modify the surfaces of cells directly to incorporate novel functionalities is highly desirable. However, genetic methods for cell-surface engineering are laborious and limited by low efficiency for primary cell modification. Here we report a chemoenzymatic approach that exploits a fucosyltransferase to transfer bio-macromolecules, such as an IgG antibody (MW∼ 150 KD), to the glycocalyx on the surfaces of live cells when the antibody is conjugated to the enzyme's natural donor substrate GDP-Fucose. Requiring no genetic modification, this method is fast and biocompatible with little interference to cells' endogenous functions. We applied this method to construct two antibody-cell conjugates (ACCs) using both cell lines and primary cells, and the modified cells exhibited specific tumor targeting and resistance to inhibitory signals produced by tumor cells, respectively. Remarkably, Herceptin-NK-92MI conjugates, a natural killer cell line modified with Herceptin, exhibit enhanced activities to induce the lysis of HER2+ cancer cells both ex vivo and in a human tumor xenograft model. Given the unprecedented substrate tolerance of the fucosyltransferase, this chemoenzymatic method offers a general approach to engineer cells as research tools and for therapeutic applications.