QUANTITATIVE STUDIES OF HETEROPOLYMER-MEDIATED BINDING OF INACTIVATEDMARBURG VIRUS TO THE COMPLEMENT RECEPTOR ON PRIMATE ERYTHROCYTES

Previous in vitro and in vivo experiments in our laboratory have demon strated that cross-linked bispecific monoclonal antibody (mAb) complex es (Heteropolymers, HP) facilitate binding of prototype pathogens to p rimate erythrocytes (E) via the E complement receptor, CR1. These E-bo und immune complexes are safely and rapidly cleared from the bloodstre am. In order to generate a robust bispecific system for HP-mediated cl earance of real pathogens such as Filoviruses, we have developed the n ecessary methodologies and reagents using both inactivated Marburg vir us (iMV) and a recombinant form of its surface envelope glycoprotein ( rGP). We identified mAbs which bind rGP in solution phase immunoprecip itation experiments. HP were prepared by chemically cross-linking an a nti-CR1 mAb with several of these anti-Marburg virus mAbs and used to facilitate binding of IMV and rGP to monkey and human E. These HP medi ate specific and quantitative binding (greater than or equal to 90%) o f both antigens to monkey and human E. Binding was also demonstrable i n an indirect RIA. E with bound Marburg virus were probed with I-125 l abeled mAbs to the Marburg surface glycoprotein and more than 100 mAbs are bound per E. It should be possible to adapt this general approach to other pathogens, and experiments underway should lead to an in viv o test of HP-mediated clearance of Marburg virus. (C) 1998 Elsevier Sc ience B.V.