scholarly journals Glycosylation of CD44 negatively regulates its recognition of hyaluronan.

1995 ◽  
Vol 182 (2) ◽  
pp. 419-429 ◽  
Author(s):  
S Katoh ◽  
Z Zheng ◽  
K Oritani ◽  
T Shimozato ◽  
P W Kincade
Keyword(s):  
B Cells ◽  
Ligand Binding ◽  
Chinese Hamster Ovary ◽  
Chinese Hamster Ovary Cells ◽  
Chinese Hamster ◽  
Surface Characteristics ◽  
Cell Types ◽  
Neuraminidase Treatment ◽  
Ovary Cells ◽  
Transitional State

Although CD44 is expressed on a wide variety of cell types, few of them use it to recognize the ligand hyaluronan (HA). A glycosylation-defective clone of Chinese hamster ovary cells (Lec 8) bound HA, demonstrating that complete processing of glycoproteins with addition of a full complement of sialic acid is not required. On the contrary, subsequent findings revealed that complex sugars on CD44 can actually inhibit ligand recognition. Two subclones of wild-type Chinese hamster ovary cells with similar amounts of surface CD44 were isolated on the basis of HA binding and found to differ with respect to CD44 size as well as staining with fluorescent lectins. Treatment of the nonbinding clone with tunicamycin reduced the size of the protein and allowed the cells to recognize HA via CD44. This function was also induced by treatment with deglycosylating enzymes (either a mixture of endoglycosidase F and N-glycosidase F or neuraminidase alone). A possible role for glycosylation in regulation of adhesion was then sought with a series of normal and transformed murine cells. Disruption of glycosylation or treatment with deglycosylating enzymes did not induce ligand binding in an interleukin 7-dependent pre-B cell line, and splenic B cells also appeared to be in an inactive state. Some normal B cells acquired the ability to recognize HA after stimulation with lipopolysaccharide or interleukin 5 and had distinctive surface characteristics (loss of immunoglobulin D and acquisition of CD43). An additional subset of activated cells might have been in a transitional state, because the cells bound ligand after neuraminidase treatment. The ligand-binding ability of a purified CD44-immunoglobulin fusion protein dramatically increased after neuraminidase treatment. Thus, differential glycosylation of this molecule is sufficient to influence its recognition function. Cell adhesion involving HA can be regulated by multiple mechanisms, one of which involves variable glycosylation of CD44.

Impaired cell volume regulation in Na(+)-H+ exchange-deficient mutants

1989 ◽  
Vol 257 (6) ◽  
pp. C1158-C1165 ◽  
Author(s):  
D. Rotin ◽  
S. Grinstein
Keyword(s):  
Chinese Hamster Ovary ◽  
Volume Regulation ◽  
Chinese Hamster Ovary Cells ◽  
Cell Volume Regulation ◽  
Chinese Hamster ◽  
Cell Types ◽  
Influx Rate ◽  
Volume Increase ◽  
Ovary Cells ◽  
Na Uptake

To elucidate the mechanism of regulatory volume increase (RVI) in Chinese hamster ovary cells, Na(+)-H+ exchange-deficient mutants, called AP-1, were derived from WT-5 cells, a wildtype subclone. The absence of functional antiports in AP-1 cells was established through measurements of intracellular pH (pHi) and Na+ uptake. Cells exposed to hypotonic medium initially swelled but regained near-normal volume within minutes. When isotonicity was then restored, WT-5 cells shrank immediately and then carried out RVI, which was inhibited by 0.1 mM amiloride. This amiloride-sensitive RVI was absent in the AP-1 mutants, suggesting involvement of Na(+)-H+ exchange. In some cell types, RVI is mediated by Na(+)-K(+)-2Cl- cotransport. Bumetanide-sensitive 86Rb+ (K+) influx was detectable in both WT-5 and AP-1 cells, suggesting the presence of Na(+)-K(+)-2Cl- cotransport. Bumetanide-sensitive influx was stimulated by osmotic shrinking in WT-5 cells, and only slightly in AP-1 cells. However, Na(+)-K(+)-2Cl- cotransport did not contribute to volume regulation, since bumetanide (50 microM) failed to inhibit RVI in osmotically shrunken WT-5 cells. The inability of cotransport to induce a volume gain in WT-5 cells was attributable to the simultaneous stimulation of Na(+)-K(+)-2Cl- efflux. The rate of efflux was similar in magnitude to the corresponding influx rate so that net Na(+)-K(+)-2Cl- cotransport was negligible. These results show that RVI in osmotically shrunken Chinese hamster ovary cells is mediated by the Na(+)-H+ antiport and that, although stimulated, Na(+)-K(+)-2Cl- cotransport does not contribute to anisosmotic volume regulation.

Amplification and expression of heterologous ornithine decarboxylase in Chinese hamster cells

1988 ◽  
Vol 8 (2) ◽  
pp. 764-769
Author(s):  
T R Chiang ◽  
L McConlogue
Keyword(s):  
Ornithine Decarboxylase ◽  
Chinese Hamster Ovary ◽  
Chinese Hamster Ovary Cells ◽  
Chinese Hamster ◽  
Cell Types ◽  
Wild Type ◽  
Dominant Marker ◽  
Ovary Cells ◽  
Mammalian Expression ◽  
Mammalian Expression Vector

We have developed an amplifiable mammalian expression vector based on the enzyme ornithine decarboxylase (ODC). We show greater than 700-fold amplification of this vector in ODC-deficient Chinese hamster ovary cells. A passive coamplified marker, dihydrofolate reductase (dhfr), was amplified and overexpressed 1,000-fold. This ODC vector was a dominant marker in a variety of cell types and displayed at least 300-fold amplification in wild-type Chinese hamster ovary cells.

scholarly journals Amplification and expression of heterologous ornithine decarboxylase in Chinese hamster cells.

1988 ◽  
Vol 8 (2) ◽  
pp. 764-769 ◽  
Author(s):  
T R Chiang ◽  
L McConlogue
Keyword(s):  
Ornithine Decarboxylase ◽  
Chinese Hamster Ovary ◽  
Chinese Hamster Ovary Cells ◽  
Chinese Hamster ◽  
Cell Types ◽  
Wild Type ◽  
Dominant Marker ◽  
Ovary Cells ◽  
Mammalian Expression ◽  
Mammalian Expression Vector

We have developed an amplifiable mammalian expression vector based on the enzyme ornithine decarboxylase (ODC). We show greater than 700-fold amplification of this vector in ODC-deficient Chinese hamster ovary cells. A passive coamplified marker, dihydrofolate reductase (dhfr), was amplified and overexpressed 1,000-fold. This ODC vector was a dominant marker in a variety of cell types and displayed at least 300-fold amplification in wild-type Chinese hamster ovary cells.

scholarly journals Ligand binding specificities of the eight types and subtypes of the mouse prostanoid receptors expressed in Chinese hamster ovary cells

1997 ◽  
Vol 122 (2) ◽  
pp. 217-224 ◽  
Author(s):  
Michitaka Kiriyama ◽  
Fumitaka Ushikubi ◽  
Takuya Kobayashi ◽  
Masakazu Hirata ◽  
Yukihiko Sugimoto ◽  
...  
Keyword(s):  
Ligand Binding ◽  
Chinese Hamster Ovary ◽  
Chinese Hamster Ovary Cells ◽  
Chinese Hamster ◽  
Prostanoid Receptors ◽  
Ovary Cells

Malignancy-related characteristics of wild type and drug-resistant chinese hamster ovary cells

Pathology ◽  
1993 ◽  
Vol 25 (3) ◽  
pp. 268-276 ◽  
Author(s):  
Wanda B. Mackinnon ◽  
Marlen Dyne ◽  
Rebecca Hancock ◽  
Carolyn E. Mountford ◽  
Adrienne J. Grant ◽  
...  
Keyword(s):  
Chinese Hamster Ovary ◽  
Chinese Hamster Ovary Cells ◽  
Chinese Hamster ◽  
Drug Resistant ◽  
Wild Type ◽  
Ovary Cells

Review of the current methods of Chinese Hamster Ovary (CHO) cells cultivation for production of therapeutic protein

2020 ◽  
Vol 17 ◽  
Author(s):  
Shazid Md. Sharker ◽  
Md. Atiqur Rahman
Keyword(s):  
Chinese Hamster Ovary ◽  
Cho Cells ◽  
Mass Production ◽  
Chinese Hamster Ovary Cells ◽  
Chinese Hamster ◽  
Therapeutic Protein ◽  
Specific Productivity ◽  
Ovary Cells ◽  
Further Development ◽  
Interesting Area

Most of clinical approved protein-based drugs or under in clinical trial have a profound impact in the treatment of critical diseases. The mammalian eukaryotic cells culture approaches, particularly the CHO (Chinese Hamster Ovary) cells are mainly used in the biopharmaceutical industry for the mass-production of therapeutic protein. Recent advances in CHO cell bioprocessing to yield recombinant proteins and monoclonal antibodies have enabled the expression of quality protein. The developments of cell lines are possible to upgrade specific productivity. As a result, it holds an interesting area for academic as well as industrial researchers around the world. This review will concentrate on the recent progress of the mammalian CHO cells culture technology and the future scope of further development for the mass-production of protein therapeutics.

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