Evidence for the Role of a Second Fc-Binding Receptor in Placental IgG Transfer in Nonhuman Primates
Yvonne J. Rosenberg, Tracy Ordonez, Urjeet S. Khanwalkar, Philip Barnette, Shilpi Pandey, Iara M. Backes, Claire E. Otero, Benjamin S. Goldberg, Andrew R. Crowley, David A. Leib, Mariya B. Shapiro, Xiaoming Jiang, Lori A. Urban, Jonathan Lees, Ann J. Hessell, Sallie R. Permar, Nancy L. Haigwood, Margaret E. Ackerman
Abstract
This study compared the ability of several human HIV envelope-directed monoclonal antibodies produced in plants with the same antibodies produced in mammalian cells for their ability to cross monkey and mouse placentas. We found that the two types of antibodies have comparable transfer efficiencies in mice, but they are differentially transferred across macaque placentas, consistent with a two-receptor IgG transport model in primates. Importantly, plant-produced monoclonal antibodies have excellent binding characteristics for human FcRn receptors, permitting desirable pharmacokinetics in humans. The lack of efficient transfer across the primate placenta suggests that therapeutic plant-based antibody treatments against autoimmune diseases and cancer could be provided to the mother while avoiding transfer and preventing harm to the fetus.