Background: The antibody response to hepatitis B surface antigen (HBsAg) controls hepatitis B virus infection. The "a" determinant of HBsAg is the most important target for protective antibody response, diagnosis and immunoprophylaxis. Mutations in this area may induce immune escape mutants and affect the performance of HBsAg assays. Objectives: To construct clinically relevant recombinant muta...

the optimization of cell culture conditions for growth and productivity of recombinant chinese hamster ovary (cho) cells is a critical step in biopharmaceutical manufacturing. in the present study, the effects of the timing and amount of peptone feeding of a recombinant cho cell line grown in a basal medium in serum-free suspension culture were determined for eight peptones of different origin ...

We have examined the involvement of insulin receptor (IR) substrate-1 (IRS-1) and/or Shc in the upstream of Ras activation in insulin signaling using Chinese hamster ovary (CHO) cell lines overexpressing wild-type (CHO-IR) cells) or mutant insulin receptors. In CHO-IR cells, insulin rapidly phosphorylated IRS-1 and Shc at tyrosine residues and stimulated the formation of the active GTP-bound Ra...

objective: bone morphogenetic protein-7 (bmp-7) is a multifunctional growth factor predominantly recognized for its osteoinductive properties. due to the high cost of this protein, the availability of bmp-7 for treatment is limited. the heterologous production of recombinant hbmp-7 has been performed in a number of expression systems. in this study a novel form of bmp-7 was expressed in eukaryo...

The role of cell surface heparan sulfate in herpes simplex virus (HSV) infection was investigated using CHO cell mutants defective in various aspects of glycosaminoglycan synthesis. Binding of radiolabeled virus to the cells and infection were assessed in mutant and wild-type cells. Virus bound efficiently to wild-type cells and initiated an abortive infection in which immediate-early or alpha ...

background toxoplasmosis is an opportunistic protozoan infection with a high prevalence in a broad range of hosts infecting up to one-third of the world human population. toxoplasmosis leads to serious medical problems in immunocompromised individuals and fetuses and also induces abortion and mortality in domestic animals. therefore, there is a huge demand for the development of an effective va...

An unsaturated fatty acid-requiring mutant derived from Chinese hamster ovary (CHO) cells has been isolated and characterized. This mutant grows normally when oleate or other unsaturated fatty acids are supplemented in the growth medium. Unlike the wild-type CHO cells, growth stops when medium is deprived of unsaturated fatty acid. Whole cell pulse experiments with [14C]acetate or [14C]stearate...

mammalian expression systems, due to their capacity in post-translational modification, are preferred systems for biopharmaceutical protein production. several recombinant protein systems have been introduced to the market, most of which are under clinical development. in spite of significant improvements such as cell line engineering, introducing novel expression methods, gene silencing and pr...

Phosphatidylserine (PS) in mammalian cells is synthesized through the exchange of free L-serine with the base moiety of phosphatidylcholine or phosphatidylethanolamine (PE). The serine base exchange in Chinese hamster ovary (CHO) cells is catalyzed by at least two enzymes, PS synthase (PSS) I and II. A PSS I-lacking mutant of CHO-K1 cells, PSA-3, which exhibits approximately 2-fold lower serine...

We have isolated, following one-step mutagenesis, a Chinese hamster ovary cell mutant hypersensitive to the intercalating agent, adriamycin (4-fold compared to parental CHO-K1 cells). This agent exerts at least part of its cytotoxic action via inhibition of the nuclear enzyme, topoisomerase II. The mutant, designated ADR-3, showed hypersensitivity to all classes of topoisomerase II inhibitors, ...