Characterization andlarge production ofhuman monoclonal antibodies against theHIV-1envelope

SUMMARY Peripheral blood lymphocytes from avolunteer immunized with arecombinant vaccinia virus VSC25expressing thegpl6O envprotein ofHTLV-IIIB strain andfroman asymptomatic HIV-infected individual were immortalized byEpstein-Barr (EBV).Clones whichsecrete humanmonoclonal antibodies fromthetwoindividuals (DZ,IgGl, AandC31,IgGl, K)wereobtained andwere stable for more than2years.Thetwomonoclonals weredirected against the gp160 envprotein ofHIV,DZ directed against thegp4landC31directed against thegpl20.C31was group-specific, whereas DZ was directed against theHTLV-IIIB andHTLV-RFstrains. Theepitope recognized byDZ was mappedtothecarboxy terminus ofthegp4l, byexpression ofHIVDNA fragments inayeastsystem andpeptide analysis. TheC31epitope was notexpressed bytheyeastlibrary andnotpresent among thepeptides which weretested. Monoclonal antibodies hadno inhibitory effect inan HIV-induced cell fusion assay,butDZshowed aweakneutralizing activity against theHTLV-IIIB strain. Cloned EBV-transformed cell lines werefused toamurine myeloma, which allowed theheteromyeloma tobe cultivated inserum-free medium. Themonoclonal antibodies wereproduced inlarge quantity ina hollow-fibre reactor atdefined culture conditions andpurification procedures.