James P. Merryweather
Chiron Corporation
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Featured researches published by James P. Merryweather.
Cellular Immunology | 1985
Andrew R. E. Shaw; R. Chris Bleackley; James P. Merryweather; Philip J. Barr
Recombinant human IL-2, secreted by yeast harboring a plasmid containing a synthetic IL-2 gene, is biologically active in augmenting human natural killer (NK) cell activity. A dose-dependent linear stimulation of NK activity was obtained against the chronic myelogenous leukemia cell line K562 over the range of 3 to 300 units/ml of IL-2. Enhancement of NK activity was similarly demonstrable against the less NK-sensitive carcinoma cell lines LoVo and SKOSC. IL-2 could also be demonstrated to augment antibody-dependent cellular cytotoxicity (ADCC) against SKOSC targets. IL-2 responsiveness segregated with a non-E-rosetting fraction comprising 11% of postfractionation lymphocytes, and containing 94% of the recoverable NK activity, suggesting that IL-2 might operate directly upon the NK cell rather than through an accessory cell. This is believed to be the first demonstration of NK stimulatory activity by the product of a totally synthetic human IL-2 gene. The availability, purity, and NK-enhancing properties of the recombinant IL-2 make it a potentially important agent for clinical trial.
FEBS Journal | 1991
Klaus Steube; Bhabatosh Chaudhuri; Walter Märki; James P. Merryweather; Jutta Heim
A synthetic gene coding for human-insulin-like growth factor I (IGFI) was fused to the leader sequence of yeast prepro-alpha-factor and expressed in Saccharomyces cerevisiae under the control of a glyceraldehyde-3-phosphate dehydrogenase promoter fragment. Recombinant IGFI was found inside yeast cells and secreted into the medium. The secreted IGFI migrated on SDS gels with the same electrophoretic mobility as authentic IGFI, i.e. at about 7.5 kDa. HPLC analysis of secreted IGFI revealed the presence of the correctly folded, genuine molecule as well as an isomeric byproduct of equal molecular mass but with two of the three disulfide bonds interchanged. Inside exponentially growing cells the 7.5-kDa IGFI was also found, along with up to four additional IGFI-related polypeptides of higher molecular mass. By endoglycosidase F treatment the three polypeptides between 19-26 kDa were converted to a single peptide of 17 kDa. Since this peptide also reacted with an anti-alpha-factor antibody, it represents most likely the unglycosylated alpha-factor--IGFI fusion precursor. Pulse-chase experiments established the precursor nature of the intracellular higher-molecular-mass IGFI species. Conversion of the primary translation product to the differently glycosylated IGFI precursor proteins and into the mature form occurred very rapidly, within 2 min. Rapid maturation was, however, not followed by an equally rapid secretion of the mature form into the medium: only after 30-40 min did IGFI appear outside the cells. We therefore postulate the presence of an as yet undefined Golgi or post-Golgi bottleneck representing a major obstacle in secretion of recombinant IGFI from S. cerevisiae cells.
Gene | 1989
Jeffrey R. Shuster; Donna L. Moyer; Helen Lee; Amy Dennis; Beth Smith; James P. Merryweather
The production of extracellular human insulin-like growth factor I (IGF-I) in yeast is deleterious to the growth of the host organism. Mutants resistant to the toxic effects of IGF-I production were isolated. A subset of these mutants produced levels of IGF-I greater than the parent strain and were due to chromosomal recessive mutations at a single locus, hpx1. The overproduction of IGF-I was independent of the original promoter and vector expression system. The mutant strains also displayed enhanced extracellular production of other heterologous proteins.
Somatic Cell and Molecular Genetics | 1985
Graeme I. Bell; Leslie B. Rall; Ray Sanchez-Pescador; James P. Merryweather; James Scott; Roger L. Eddy; Thomas B. Shows
A cDNA clone encoding amino acids 809–1451 of the protease inhibitor α2-macroglobulin has been isolated from an adult human liver cDNA library. This cDNA was used to examine DNA samples prepared from a panel of human-mouse somatic cell hybrids with different numbers and combinations of human chromosomes for the presence of the human α2-macroglobulin gene. The cosegregation of this gene and chromosome 12 in the cell hybrid panel indicated that the α2-macroglobulin structural gene (designated A2M) is on human chromosome 12.
Nature | 1984
Graeme I. Bell; James P. Merryweather; Ray Sanchez-Pescador; Michelle M. Stempien; Linda Priestley; James Scott; Leslie B. Rall
Archive | 1986
Lawrence S. Cousens; Patricia Tekamp-Olson; Jeffrey R. Shuster; James P. Merryweather
Archive | 1986
Lawrence S. Cousens; Patricia Tekamp-Olson; Jeffrey R. Shuster; James P. Merryweather
Biochemistry | 1988
Carlos George-Nascimento; Alexander Gyenes; S. Mitchell Halloran; James P. Merryweather; Pablo Valenzuela; Kathelyn S. Steimer; Frank R. Masiarz; Anne Randolph
Archive | 1984
Philip J. Barr; James P. Merryweather; Guy Mullenbach; Mickey S. Urdea
Archive | 1987
Philip J. Barr; James P. Merryweather; Guy Mullenbach; Mickey S. Urdea; Pablo Valenzuela