EXPRESSION OF THE RECOMBINANT ANCHORLESS N-TERMINAL DOMAIN OF MOUSE HEPATITIS-VIRUS (MHV) RECEPTOR MAKES HAMSTER OR HUMAN-CELLS SUSCEPTIBLETO MHV INFECTION

Mouse hepatitis virus (MHV) receptor, the receptor for the murine coro navirus MHV, was expressed in MHV-resistant hamster and human cells as a series of mutant, recombinant glycoproteins with carboxyterminal de letions lacking the cytoplasmic tail, transmembrane domain, and variou s amounts of the immunoglobulin constant-region-like domains. The solu ble receptor glycoproteins containing the N-terminal virus-binding dom ain were released into the supernatant medium and inactivated the infe ctivity of MHV-A59 virions in a concentration-dependent manner. Surpri singly, some of the anchorless glycoproteins were found on the plasma membranes of transfected cells by flow cytometry, and these cells were rendered susceptible to infection with three strains of MHV, Thus, in the cells in which the anchorless, recombinant receptor glycoprotein is synthesized, some of the protein is bound to an unidentified moiety on the plasma membrane, which allows it to serve as a functional viru s receptor.