Pluripotent stem cells evade replicative senescence, whereas other primary cells lose their proliferation and differentiation potential after a limited number of cell divisions, and this is accompanied by specific senescence-associated DNA methylation (SA-DNAm) changes. Here, we investigate SA-DNAm changes in mesenchymal stromal cells (MSC) upon longterm culture, irradiation-induced senescence, immortalization, and reprogramming into induced pluripotent stem cells (iPSC) using high-density HumanMethylation450 BeadChips. SA-DNAm changes are highly reproducible and they are enriched in intergenic and nonpromoter regions of developmental genes. Furthermore, SA-hypomethylation in particular appears to be associated with H3K9me3, H3K27me3, and Polycomb-group 2 target genes. We demonstrate that ionizing irradiation, although associated with a senescence phenotype, does not affect SA-DNAm. Furthermore, overexpression of the catalytic subunit of the human telomerase (TERT) or conditional immortalization with a doxycyclineinducible system (TERT and SV40-TAg) result in telomere extension, but do not prevent SA-DNAm. In contrast, we demonstrate that reprogramming into iPSC prevents almost the entire set of SA-DNAm changes. Our results indicate that long-term culture is associated with an epigenetically controlled process that stalls cells in a particular functional state, whereas irradiation-induced senescence and immortalization are not causally related to this process. Absence of SADNAm in pluripotent cells may play a central role for their escape from cellular senescence.

The process for CD34 selection with Prodigy is robust and labor-saving but not time-saving. Compared with clinical CD34+ selected products concurrently generated with the predecessor technology, product properties, importantly including CD34+ cell recovery and T-cell contents, were not significantly different. The automatic system is suitable for routine clinical application.

BackgroundAutomation of cell therapy manufacturing promises higher productivity of cell factories, more economical use of highly-trained (and costly) manufacturing staff, facilitation of processes requiring manufacturing steps at inconvenient hours, improved consistency of processing steps and other benefits. One of the most broadly disseminated engineered cell therapy products is immunomagnetically selected CD34+ hematopoietic “stem” cells (HSCs).MethodsAs the clinical GMP-compliant automat CliniMACS Prodigy is being programmed to perform ever more complex sequential manufacturing steps, we developed a CD34+ selection module for comparison with the standard semi-automatic CD34 “normal scale” selection process on CliniMACS Plus, applicable for 600 × 106 target cells out of 60 × 109 total cells. Three split-validation processings with healthy donor G-CSF-mobilized apheresis products were performed; feasibility, time consumption and product quality were assessed.ResultsAll processes proceeded uneventfully. Prodigy runs took about 1 h longer than CliniMACS Plus runs, albeit with markedly less hands-on operator time and therefore also suitable for less experienced operators. Recovery of target cells was the same for both technologies. Although impurities, specifically T- and B-cells, were 5 ± 1.6-fold and 4 ± 0.4-fold higher in the Prodigy products (p = ns and p = 0.013 for T and B cell depletion, respectively), T cell contents per kg of a virtual recipient receiving 4 × 106 CD34+ cells/kg was below 10 × 103/kg even in the worst Prodigy product and thus more than fivefold below the specification of CD34+ selected mismatched-donor stem cell products. The products’ theoretical clinical usability is thus confirmed.ConclusionsThis split validation exercise of a relatively short and simple process exemplifies the potential of automatic cell manufacturing. Automation will further gain in attractiveness when applied to more complex processes, requiring frequent interventions or handling at unfavourable working hours, such as re-targeting of T-cells.

of different scales from 5 ml to 500 ml. Optimization of transfection parameters like cell density at the time of transfection, the ratio of helper to donor plasmid and total plasmid to PEI was conducted for each individual cell line. Lysates and supernatants were processed separately using gradient centrifugation and affinity chromatography. Purified virus stocks were then analyzed and titrated using methods to determine total viral particles, viral genomes and infectious titers. Preliminary results indicate that rAAV particles produced with suspension cells yield infectious titers equal or higher than particles produced by standard methods based on adherent cells. Further work is ongoing to analyze and implement this OSR platform. The presented process offers a novel method to produce rAAV for preclinical and clinical trials compliant to GMP, single-use and scalable.

This "first-in-man" study demonstrated the safety and feasibility of manufacturing both CD34-TK75+ T cells and [ 18 F]FHBG onsite for administration to patients. A future upfront haploidentical transplant study will employ 100-fold more CD34-TK75 modified T cells.