Isolation and characterization of mouse-human somatic cell hybrids which produce a leukemia associated antigen

Interspeci fic somatic cell hybridisation has the potential not only of producing hybrids expressing antigens o-f two different species but also of providing genetic information on these foreign antigens. The work presented here, describes the successful interspecific somatic cell hybridisation of a mouse myeloid cell line (WeHi-TG) with peripheral blood leukocytes from a patient with chronic granulocytic leukemia. Hybrid fusion products were screened for their ability to produce a leukemia associated protein (CAMAL) as detected by indirect immunoperoxidase as well as ELISA using a monoclonal antibody specific for CAMAL. Production of this antigen was verified by immunoprecipitation of internally labelled cell lysates from these hybridomas. CAMAL-producing cell hybrids were further tested for the prescence of human DNA, using the BLUR 8 "Alu" containing DNA probe and a panel of monoclonal antibodies with specificities to a variety of myeloid antigens. These studies confirmed the prescence of human DNA and showed some correlation between cells producing CAMAL and those expressing other granulocyte markers. Karyotype analysis was carried out on hybridoma lines after long term culture. In all hybrids examined, no recognizable human chromosomes or translocations were detected using either the methods of G-banding or differential G-ll staining. The development of an in vivo animal model for human leukemia would provide a mammalian system for the testing of various cancer therapies. The ability of our CAMAL expressing hybrids to grow in BALB/C mice provided the rationale for the development of an animal model for cancer therapy. Our preliminary in vitro results showed that CAMAL expressing hybrids could be specifically eliminated using hematoporphyrin conjugated to CAMAL-1.Science, Faculty ofMicrobiology and Immunology, Department ofGraduat