ABSTRACT
Somatic cell hybridization techniques have allowed the preparation of interspecies hybrids that express the features of both parental cell lines. We have studied hybrids made with human myeloma cells fused to a continuous mouse myeloma cell line. In the present study we analyzed the kinetics of leucine influx and efflux in Ig producer and nonproducer hybrids. We found no statistical difference in amino acid influx; however, the rates of efflux were markedly increased in nonproducer hybrids as compared to the producers. The producer cells were tested further in puromycin known to inhibit protein synthesis. Under these conditions amino acid influx was not altered, but efflux was markedly increased resembling the findings in nonproducers. We conclude that hybrids that synthesize human immunoglobulins show decreased efflux of labeled leucine and this effect can be abolished by inhibition of protein synthesis. This difference in the efflux rate appears to be a consequence of immunoglobulin synthesis, rather than a component of a control mechanism of Ig synthesis.
Subject(s)
Amino Acids/metabolism , Hybrid Cells/metabolism , Immunoglobulins/biosynthesis , Multiple Myeloma/metabolism , Animals , Biological Transport , Humans , Leucine/metabolism , Mice , Puromycin/pharmacologyABSTRACT
Several monoclonal antibodies to rat lung angiotensin-converting enzyme (ACE) have been produced. The antibodies are of the IgG class, do not inhibit ACE catalytic activity, and do not cross-react with the human or bovine enzyme. They bind in a curvilinear fashion to lung capillary endothelium by immunofluorescence microscopy, and radiolabeled antibody localizes in lung and other organs after intravenous injection into living rats. Each antibody tested appears to bind preferentially to lung rather than kidney ACE by ELISA, a finding supported by weak or absent immunofluorescence of kidney slices in vitro. These antibodies may be used to probe structural differences between ACE in various tissues and, by quantitating changes in accumulation of radiolabeled antibody in experimental models of lung injury, should complement functional measurements in determining the presence of subtle and progressive endothelial damage.
Subject(s)
Antibodies, Monoclonal , Epitopes/analysis , Lung/enzymology , Peptidyl-Dipeptidase A/analysis , Animals , Antigen-Antibody Complex , Cattle , Cross Reactions , Fluorescent Antibody Technique , Humans , Immunoglobulin G , Mice , Mice, Inbred BALB C , Peptidyl-Dipeptidase A/immunology , Rats , Species SpecificityABSTRACT
Human myeloma cells from a patient suffering from a lambda Bence-Jones myeloma were hybridized with a continuous mouse myeloma cell line. Several hybrids were obtained, two of which produced the same lambda chain produced by the patient. They have proved to be stable over long periods of time in continuous cell culture. Kinetics of growth of this line proved to be linear over 72 h. This growth rate is independent of any possible nutrient depletion effect from the media. Rate of production of lambda chain was highest (45 micrograms/10(6) cells/24 h) when cell density was between 3-5 X 10(5)/ml and decreased as cell density increased. Efficiency of human light chain synthesis in these hybrids is similar to murine Ig synthesis by the producer parental mouse cells. Human-mouse myeloma hybrids that produce large quantities of human Igs can be established routinely, are stable over long periods of time, and can be used as a model system for the study of the control of synthesis of human Igs.
