Cassette baculovirus vectors for the production of chimeric, humanized, or human antibodies in insect cells

Plasmid cassette‐transfer vectors pBHuCϰ and pBHuCy1 have been designed which enable the construction of recombinant baculoviruses directing the co‐expression of complete immunoglobulin in insect cells. We describe the application of these vectors for the expression of a human/mouse chimeric monoclonal antibody of potential immunosuppressive clinical value derived from a mouse anti‐human CD29 monoclonal antibody (Mu‐K20). The chimeric K20 light and heavy chains produced in sf9 insect cells were correctly processed and assembled into a normal immunoglobulin which is secreted into the culture medium of infected cells. The chimeric mAb Ch‐K20‐sf9 reproduces in vitro the functional properties of the parental mouse K20, including affinity and inhibition of lymphocyte proliferation. These results demonstrate that the baculovirus/insect cell expression system is suitable for the expression of fully active monoclonal antibodies of therapeutic value. Our generic cassette approach makes this system a very flexible and convenient one for the rapid production of either chimeric, humanized or human mAb with heavy and light chains of any isotype.