S L Swanberg | PubMed Health

PubMed1992

High level expression on a chimeric anti-ganglioside GD2 antibody: genomic kappa sequences improve expression in COS and CHO cells.

We report a flexible strategy for the high level expression of a recombinant human monoclonal antibody (mAb) in Chinese hamster ovary (CHO) cells, initially using COS monkey kidney cell transfections to evaluate rapidly modifications to immunoglobulin (Ig) DNA constructs. Using sequential transfections with two amplifiable markers, we generated CHO cell lines and clones that secrete 80-110 micrograms/10(6) cells/24 hours of a mouse-human chimeric IgG1 kappa mAb. This cellular productivity is considerably greater than most murine hybridomas and transfected myelomas. Our data also demonstrate that genomic kappa sequences can improve mAb expression in COS and CHO cells. As a paradigm, we focused our expression studies on a human chimeric form of 3F8, a murine mAb that binds to ganglioside GD2 on neuroblastoma and melanoma tumor cells.

Animals↗

PubMed1978

Some characteristics of Ureaplasma urealyticum. Urease activity in a simple buffer: effect of metal ions and sulphydryl inhibitors.

Urealytic activity of the cytoplasmic fraction of Ureaplasma urealyticum prepared by digitonin lysis was assayed in a simple buffer system (HEPES plus EDTA) by measuring the release of 14CO2 from [14C]urea. The Km of this preparation agreed with our previous observations of the same activity measured in a more complex reaction mixture. The substrate concentration at which maximum velocity occurred was approximately 20 mM. The activity was sensitive to heavy metals and inhibitors which react with sulphydryl groups such as N-ethylmaleimide and p-chloromercuribenzoate. It was not inhibited by Ca2+ or Mg2+ or by the reaction products, ammonia and carbon dioxide.

Culture Media↗