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Published in Ronald Fayer, Lihua Xiao, Cryptosporidium and Cryptosporidiosis, 2007
Secondary human lung fibroblast cells (MRC-5 cells, ECACC, Salisbury) supported development of C. parvum and C. hominis and were used to evaluate oocyst survival under conditions mimicking various food environments (Dawson et al., 2004). Oocysts from human stools (C. hominis) were purified over saturated NaCl flotation. Oocysts of C. parvum originally isolated from deer and passaged in lambs were obtained from a commercial source. MRC-5 cells were grown in Medium 199 containing Earle’s salts, essential amino acids, and L-glutamine and was supplemented with 0.075% sodium bicarbonate, 10% FCS, 3 mg/mL sodium benzylpenicillin, and 160 µg/mL gentamycin. When oocysts were inoculated, the medium also contained 20 µg/mL amphotericin B. Oocysts were not treated with bleach or excystation solutions before inoculation into cell cultures. After incubation for 5 days at 37°C in a 5% CO2 incubator, cultures were fixed with acetone, stained with auramine-phenol, and examined with the aid of a fluorescence microscope. Fluorescing structures in 5 or 10 randomly selected microscopic fields (200 or 400× total magnification) were counted and infectivity estimated. No microscopic images were provided in the publication, and no specific life-cycle stages were identified.
Overview of Cell Culture Processes
Published in Wei-Shou Hu, Cell Culture Bioprocess Engineering, 2020
Cell lines have been used for the industrial production of human and veterinary vaccines for more than half a century. For human viral vaccine production, human diploid cell strains (MRC-5 in particular) are the preferred cell substrate. Traditional viral vaccines consist of whole virus particles where the viral genome is packaged in the virus particle after the replication of its genetic materials in the production cell. The entire viral particle is then injected into the patient to elicit an immune response. There is a low-level risk that the virus genome might recombine with the genetic elements of the production cell and bring the genetic element of the host cell into the virus particle. This poses a potential risk of transmitting an activated oncogenic or other adventitious genetic element to the patient. To minimize such a risk, the vast majority of human virus vaccines are produced in normal diploid human cells. Vero and MDCK cells (along with chick embryos) are notable exceptions of non-human continuous cell lines used for human vaccine production (Table 1.5). In the case that a continuous cell line is used for human vaccine production, its passage number is carefully monitored and controlled to alleviate concerns raised by the report that prolonged passage of Vero cells poses an increased risk of tumor formation.39 However, advances in molecular analytics in recent years are rapidly extending our capability to characterize cells as well as products. There is an increasing interest in exploring the use of continuous or even tumorigenic cell lines for the production of viral biologics. For veterinary vaccines, the repertoire of host cells is much larger. Both cell lines and tissue-derived cell strains with limited life spans are widely used (Table 1.6).
Methods for the Detection of Adventitious Viruses in Cell Cultures Used in the Production of Biotechnology Products
Published in Anthony S. Lubiniecki, Large-Scale Mammalian Cell Culture Technology, 2018
Hayflick and Moorhead (1961) established human diploid fetal lung cultures (WI-38) and characterized them extensively for use in virus vaccine production so that they could be used as an alternative to primary monkey cell cultures. In approximately 1969, a human fetal lung culture (MRC-5) was shown to be suitable for human vaccine production in Britain. In 1972, WI-38 was finally approved for oral poliovaccine production in the United States (Hopps, 1985).
Pharmacokinetic and anti-colon cancer properties of curcumin-containing chitosan-pectinate composite nanoparticles
Published in Journal of Biomaterials Science, Polymer Edition, 2018
Enas Alkhader, Clive J. Roberts, Rozita Rosli, Kah Hay Yuen, Eng Kwong Seow, You Zhuan Lee, Nashiru Billa
An MTT assay (3-(4,5-Dimethylthiazol-2-Yl)-2,5-Diphenyltetrazolium Bromide assay) was used to assess cell viability due to the blank and CUR-CS-PEC-NPs on HT-29 and MRC-5. MRC-5 come from normal lung fibroblasts and the major advantage of using this cell line is its capability to grow for more than 40 passages while maintaining normal diploid karyotype. Its use as control (normal) cell line against colorectal cancer cell lines have been extensively reported in the literature [35–40], therefore, it was used as the control cell line in this study.