CHARACTERIZATION OF PROTEIN INVOLVEMENT IN RABIES VIRUS BINDING TO BHK-21-CELLS

Prior studies established the specificity of rabies virus receptors on BHK-21 cells based on the saturability of the receptors and on compet itive binding. In the present study, we used protease-treated cells to identify the involvement of protein in the specific binding of rabies virus to these cells. In addition, biochemical characterization of n- octylglucoside solubilized BHK-21 plasma membranes demonstrated the in volvement of a protease sensitive, heat insensitive, integral membrane protein or protein complex in rabies virus binding to these cells. Th e membrane component that binds rabies virus is associated with a high molecular weight fraction of the n-octylglucoside-plasma membrane ext ract isolated by gel filtration. This high molecular weight fraction ( similar to 450 KDa) is enriched with a cell surface integral membrane component that comigrates with denatured bovine serum fibronectin (220 KDa). This cellular component did not bind polyclonal antisera to fib ronectin in Western blot (native or denatured) or immunoprecipitation experiments. Direct and specific virus binding to high molecular weigh t plasma membrane protein(s) separated on Western blots further confir med the role of a protein receptor in rabies virus binding to these ce lls.