HUMAN MONOCLONAL-ANTIBODIES TO CYTOMEGALOVIRUS - CHARACTERIZATION ANDRECOMBINANT EXPRESSION OF A GLYCOPROTEIN-B-SPECIFIC ANTIBODY

Human monoclonal antibodies (mAb) to human cytomegalovirus (HCMV) were established from spleen cells of a HCMV-positive donor. The antibodie s (gamma(3), lambda) secreted from a stable heterohybridoma cell line were further characterized by immunoprecipitation and immune-fluoresce nce microscopy using HCMV infected cells and recombinant cell lines ex pressing HCMV glycoprotein B. The antibody reacted with the entire gly coprotein B or the extracellular domain expressed as glycoprotein-B-be ta-galactosidase fusion protein in the native state, but the antibody was not neutralizing HCMV. Denatured and reduced forms of glycoprotein B were not recognized by this antibody, however, native glycoprotein B on the surface of infected cells was detected efficiently. The genes encoding the Fab part of the antibody were cloned and expressed in Es cherichia coli. Recombinant Fab fragments specifically binding the ext racellular domain of glycoprotein B could easily be isolated from the periplasmic space. Recombinant antibodies provide the opportunity to m odify effector functions and to add tags to diagnostic antibodies for more efficient detection of CMV-infected cells.