Antibodies to cell surface proteins redirect intracellular trafficking pathways

Abstract

Antibody-mediated intracellular delivery of therapeutic agents has been considered for treatment of a variety of diseases. These approaches involve targeting cell-surface receptor proteins expressed by tumors or viral proteins expressed on infected cells. We examined the intracellular trafficking of a viral cell-surface-expressed protein, rabies G, with or without binding a specific antibody, ARG1. We found that antibody binding shifts the native intracellular trafficking pathway of rabies G in an Fc-independent manner. Kinetic studies indicate that the ARG1/rabies G complex progressively co-localized with clathrin, early endosomes, late endosomes, and lysosomes after addition to cells. This pathway was different from that taken by rabies G without addition of antibody, which localized with recycling endosomes. Findings were recapitulated using a cellular receptor with a well-defined endogenous recycling pathway. We conclude that antibody binding to cell-surface proteins induces redirection of intracellular trafficking of unbound or ligand bound receptors to a specific degradation pathway. These findings have broad implications for future developments of antibody-based therapeutics.

Tuning Innate Immune Activation by Surface Texturing of Polymer Microparticles: The Role of Shape in Inflammasome Activation

“…Additionally, we have previously shown that uptake of antibody-bound membrane proteins can internalize via clathrin through the endosomal pathway (47). In order to further elucidate the mechanisms involved in particle internalization, WT macrophages were stained with fluorescent cholera toxin subunit B (CTxB), which binds to GM1 gangliosides on the cell surface, as a marker for lipid rafts.…”

Rabies Virus Envelope Glycoprotein Targets Lentiviral Vectors to the Axonal Retrograde Pathway in Motor Neurons

“…This might be related to the ability of the intact virus to block degradation in the cell. A recent study indicated that RV-G bound to an antibody transfected in a neuroblastoma cell line is targeted via early and late endosomes to lysosomes (58). In addition, lentiviral vector transduction of dendritic cells involved endosomal trafficking, and its efficiency was enhanced by suppressing autophagy (59).…”

Targeting Antigens through Blood Dendritic Cell Antigen 2 on Plasmacytoid Dendritic Cells Promotes Immunologic Tolerance

“…Ag internalized by these receptors must enter into the late-endosomal/lysosmal Ag pathway for degradation and presentation on MHC class II. It was recently shown that binding of mAbs to the transferrin receptor redirects its native intracellular trafficking (i.e., when bound by its natural ligand, transferrin) from recycling endosomes to late endosomal compartments (61). The extent to which mAb binding affects the internalization pathways of receptors such as BDCA2 and Siglec-H is not known and may be one factor that contributes to the differences in outcomes following targeting Ag to different receptors on pDCs (1).…”