Application of methods for viral clearance in stem cell production.
ABSTRACT Regenerative medicine therapies will allow in the future the transplant of cells of human origin in some diseases that until now have been incurable. The assurance of the safety and quality, especially from a microbiological point of view, is very important for these therapeutic products. Depending on the starting material, there are several sources of pathogen presence, mainly human viruses. Also, the use of feeders of animal origin as layers in which the stem cells can grow may permit the transmission of animal pathogens to these cells. However, cell sources are limited due to the low availability of spare in vitro fecundation human embryos and the low rate of success in the derivation of human stem cell lines. Thus, in several cases, it will be necessary to evaluate the possibility of removing or inactivating these microorganisms. In this paper, we summarize the main methods of viral clearance and we have provided an overview of the main features taking into account in the viral clearance techniques.
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ABSTRACT: Rodent cells are used widely to manufacture recombinant proteins for pharmaceutical use in humans and animals. However, all rodent cell lines express endogenous retroviruses that require appropriate testing regimes for identification and characterisation. In this communication we report the results of transmission electron microscopy, reverse transcriptase assay and infectious virus assays for retrovirus in 185 manufacturer cell banks of mouse, rat or hamster origin. The results indicated considerable variability of retroviral expression levels by transmission electron microscopy and reverse transcriptase assay, but nevertheless characteristic features of each cell type were observed. Infectious retrovirus was detected in mouse myeloma and hybridoma cell lines, but not in cell lines of hamster or rat origin. There was no evidence of contamination of cell banks with exogenous retrovirus. The results of retroviral characterisation of the parental mouse cell lines NS0, NS-1 and Sp2/0Ag14 by the above assays were consistent with the results of the survey. Co-cultivation of the above parental mouse cell lines with mouse and human cell lines suggested that the ability to infect human cells was related to threshold susceptibility of cell types and the levels of expression of infectious xenotropic retrovirus by mouse cells.Biologicals 01/2004; 31(4):251-60. DOI:10.1016/S1045-1056(03)00065-4 · 1.41 Impact Factor
- PDA journal of pharmaceutical science and technology / PDA 54(3):209-17.
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ABSTRACT: We report a phase I trial to determine the feasibility of collection, ex vivo culture-expansion and intravneous infusion of human bone marrow-derived progenitor stromal cells (mesenchymal progenitor cells (MPCs)). Ten milliliter bone marrow samples were obtained from 23 patients with hematologic malignancies in complete remission. Bone marrow mononuclear cells were separated and adherent cells were culture-expanded in vitro for 4-7 weeks. Autologous MPCs were reinfused intravenously and a bone marrow examination repeated 2 weeks later for histologic assessment and in vitro hematopoietic cultures. Patient age ranged from 18 to 68 years and 12 subjects previously had undergone an autologous or syngeneic bone marrow transplant 4-52 months prior to collection of MPCs. A median of 364 x 10(6) nucleated bone marrow cells (range: 103 to 1004 x 10(6)) were used for ex vivo expansion. Median number of MPCs which were obtained after ex vivo culture expansion was 59.0 (range: 1.1 to 347 x 10(6)) representing a median cell doubling of 16,000-fold (13 doublings). Fifteen of 23 patients completed the ex vivo expansion and underwent MPC infusion. Time to infusion of MPCs after collection ranged from 28 to 49 days. Five patients in each of three groups were given 1, 10 and 50 x 10(6) MPCs. No adverse reactions were observed with the infusion of the MPCs. MPCs obtained from cancer patients can be collected, expanded in vitro and infused intravenously without toxicity.(ABSTRACT TRUNCATED AT 250 WORDS)Bone Marrow Transplantation 11/1995; 16(4):557-64. · 3.47 Impact Factor