Production of monoclonal antibodies using recombinant baculovirus displaying gp64-fusion proteins

Generation of protein immunogens is often a rate-limiting step in the produ ction of monoclonal antibodies (Mabs). Expressing domains of proteins as fu sions to the baculovirus surface glycoprotein gp64 displays foreign protein s on the surface of the virion. Antigen is produced by inserting a gene fra gment in-frame between the signal sequence and the mature protein domain of the gp64 nucleotide sequence. This method allows immunization with whole v irus, eliminating the need for purification of target antigens. Affinity-ma tured Mabs to the human nuclear receptors LXR beta and FXR have been produc ed using baculovirus particles displaying gp64/nuclear receptor fusion prot eins as the immunizing agent. Immunizations were performed directly with pe lleted virus using the Repetitive Immunization Multiple Sites (RIMMS) immun ization strategy for rapid Mab production. All Mabs were identified using i nsect cells infected with the immunizing virus. Characterization of these a ntibodies shows them to be class-switched and specific for LXR beta or FXR. Additionally, high affinity antibodies that recognize gp64 and neutralize baculovirus infection of insect cells were isolated. Use of the recombinant baculovirus gp64 display system makes possible the production of Mabs once a partial DNA sequence is known. This allows the generation of antibodies prior to the isolation of purified protein, in turn providing antibodies to facilitate purification, characterization and immunolocalization of protei ns. (C) 2000 Elsevier Science B.V. All rights reserved.