Transition from serum-supplemented monolayer to serum-free suspension lentiviral vector production for generation of chimeric antigen receptor T cells.

Background Aims: Lentiviral vectors (LVs) have been used extensively in gene therapy protocols because of their high biosafety profile and capacity to stably express a gene of interest. Production of these vectors for the generation of chimeric antigen receptor (CAR) T cells in academic and research centers is achieved using serum-supplemented static monolayer cultures. Although efficient for pre-clinical studies, this method has a number of limitations.

Corrigendum: Successful Use of Human AB Serum to Support the Expansion of Adipose Tissue-Derived Mesenchymal Stem/Stromal Cell in a Microcarrier-Based Platform.

[This corrects the article DOI: 10.3389/fbioe.2020.

Successful Use of Human AB Serum to Support the Expansion of Adipose Tissue-Derived Mesenchymal Stem/Stromal Cell in a Microcarrier-Based Platform.

Mesenchymal stem/stromal cells (MSC) are promising candidates for cell-based therapies and for the promotion of tissue repair, hence the increase of clinical trials in a worldwide scale. In particular, adipose tissue-derived stem/stromal cells (AT MSC) present easy accessibility and a rather straightforward process of isolation, providing a clear advantage over other sources. The high demand of cell doses (millions of cells/kg), needed for infusion in clinical settings, requires a scalable and efficient manufacturing of AT MSC under xenogeneic(xeno)-free culture conditions.

Immunophenotypic Analysis of CAR-T Cells.

CAR-T cell immunotherapy is a promising therapeutic modality for cancer patients. The success of CAR-T cell therapy has been associated with the phenotype, activation and functional profiling of infused CAR-T cells. Therefore, immunophenotypic characterization of CAR-T cells during bioprocess is crucial for cell quality control and ultimately for improved antitumor efficacy.

Platforms for Clinical-Grade CAR-T Cell Expansion.

Chimeric antigen receptor (CAR)-T cell therapy has revolutionized the immunotherapy field with high rate complete responses especially for hematological diseases. Despite the diversity of tumor specific-antigens, the manufacturing process is consistent and involves multiple steps, including selection of T cells, activation, genetic modification, and in vitro expansion. Among these complex manufacturing phases, the choice of culture system to generate a high number of functional cells needs to be evaluated and optimized.

Establishment of a simple and efficient platform for car-t cell generation and expansion: from lentiviral production to in vivo studies.

Introduction: Adoptive transfer of T cells expressing a CD19-specific chimeric antigen receptor (CAR) has shown impressive response rates for the treatment of CD19 + B-cell malignancies in numerous clinical trials. The CAR molecule, which recognizes cell-surface tumor-associated antigen independently of human leukocyte antigen (HLA), is composed by one or more signaling molecules to activate genetically modified T cells for killing, proliferation, and cytokine production.

Objectives: In order to make this treatment available for a larger number of patients, we developed a simple and efficient platform to generate and expand CAR-T cells.

Proteomic Identification and Time-Course Monitoring of Secreted Proteins During Expansion of Human Mesenchymal Stem/Stromal in Stirred-Tank Bioreactor.

The therapeutic potential of mesenchymal stem/stromal cells (MSC) is widely recognized for the treatment of several diseases, including acute graft-vs.-host disease (GVHD), hematological malignancies, cardiovascular, bone, and cartilage diseases. More recently, this therapeutic efficacy has been attributed to the bioactive molecules that these cells secrete (secretome), now being referred as medicinal signaling cells.

Correction to: Priming approaches to improve the efficacy of mesenchymal stromal cell-based therapies.

The original article [1] contained an error in the presentation of the first author's name, Nádia de Cássia Noronha. This has now been corrected.

Priming approaches to improve the efficacy of mesenchymal stromal cell-based therapies.

Multipotent mesenchymal stromal cells (MSC) have been widely explored for cell-based therapy of immune-mediated, inflammatory, and degenerative diseases, due to their immunosuppressive, immunomodulatory, and regenerative potentials. Preclinical studies and clinical trials have demonstrated promising therapeutic results although these have been somewhat limited. Aspects such as low in vivo MSC survival in inhospitable disease microenvironments, requirements for ex vivo cell overexpansion prior to infusions, intrinsic differences between MSC and different sources and donors, variability of culturing protocols, and potency assays to evaluate MSC products have been described as limitations in the field.

Mesenchymal Stromal Cells: From Discovery to Manufacturing and Commercialization.

Over the last decades, mesenchymal stromal cells (MSC) have been the focus of intense research by academia and industry due to their unique features. MSC can be easily isolated and expanded through culture by taking full advantage of their self-renewing capacity. In addition, MSC exert immunomodulatory effects and can be differentiated into various lineages, which makes them highly attractive for clinical applications in cell-based therapies.

Platforms for Recombinant Therapeutic Glycoprotein Production.

The majority of FDA-approved biology-derived products are recombinant glycoproteins. These proteins have been used for the treatment of several diseases, with numerous products currently approved for clinical use. The choice of the expression system is a key step toward a successful functional protein production, since glycosylation influences yield, pharmacokinetics, biological activity, and immunogenicity.

Production of coagulation factor VII in human cell lines Sk-Hep-1 and HKB-11.

Recombinant factor VII (rFVII) is the main therapeutic choice for hemophilia patients who have developed inhibitory antibodies against conventional treatments (FVIII and FIX). Because of the post-translational modifications, rFVII needs to be produced in mammalian cell lines. In this study, for the first time, we have shown efficient rFVII production in HepG2, Sk-Hep-1, and HKB-11 cell lines.

Expansion strategies for human mesenchymal stromal cells culture under xeno-free conditions.

Choosing the culture system and culture medium used to produce cells are key steps toward a safe, scalable, and cost-effective expansion bioprocess for cell therapy purposes. The use of AB human serum (AB HS) as an alternative xeno-free supplement for mesenchymal stromal cells (MSC) cultivation has increasingly gained relevance due to safety and efficiency aspects. Here we have evaluated different scalable culture systems to produce a meaningful number of umbilical cord matrix-derived MSC (UCM MSC) using AB HS for culture medium supplementation during expansion and cryopreservation to enable a xeno-free bioprocess.

Characterization of Human AB Serum for Mesenchymal Stromal Cell Expansion.

Background: So far, using human blood-derived components appears to be the most efficient and safest approach available for mesenchymal stromal cell (MSC) expansion. In this paper, we report on the characterization of human AB serum (AB HS) produced by using different plasma sources, and its use as an alternative supplement to MSC expansion.

Methods: Two plasma sources were used for AB HS production: plasma removed from whole blood after 24 h of collection (PC > 24 h) and plasma, cryoprecipitate reduced (PCryoR).

Stirred tank bioreactor culture combined with serum-/xenogeneic-free culture medium enables an efficient expansion of umbilical cord-derived mesenchymal stem/stromal cells.

Mesenchymal stem/stromal cells (MSC) are being widely explored as promising candidates for cell-based therapies. Among the different human MSC origins exploited, umbilical cord represents an attractive and readily available source of MSC that involves a non-invasive collection procedure. In order to achieve relevant cell numbers of human MSC for clinical applications, it is crucial to develop scalable culture systems that allow bioprocess control and monitoring, combined with the use of serum/xenogeneic (xeno)-free culture media.

Combining xanthan and chitosan membranes to multipotent mesenchymal stromal cells as bioactive dressings for dermo-epidermal wounds.

The association between tridimensional scaffolds to cells of interest has provided excellent perspectives for obtaining viable complex tissues in vitro, such as skin, resulting in impressive advances in the field of tissue engineering applied to regenerative therapies. The use of multipotent mesenchymal stromal cells in the treatment of dermo-epidermal wounds is particularly promising due to several relevant properties of these cells, such as high capacity of proliferation in culture, potential of differentiation in multiple skin cell types, important paracrine and immunomodulatory effects, among others. Membranes of chitosan complexed with xanthan may be potentially useful as scaffolds for multipotent mesenchymal stromal cells, given that they present suitable physico-chemical characteristics and have adequate tridimensional structure for the adhesion, growth, and maintenance of cell function.

Growth and functional harvesting of human mesenchymal stromal cells cultured on a microcarrier-based system.

Human mesenchymal stromal cells (hMSCs) cells are attractive for applications in tissue engineering and cell therapy. Because of the low availability of hMSCs in tissues and the high doses of hMSCs necessary for infusion, scalable and cost-effective technologies for in vitro cell expansion are needed to produce MSCs while maintaining their functional, immunophenotypic and cytogenetic characteristics. Microcarrier-based culture systems are a good alternative to traditional systems for hMSC expansion.

Efficient expansion of mesenchymal stromal cells in a disposable fixed bed culture system.

The need for efficient and reliable technologies for clinical-scale expansion of mesenchymal stromal cells (MSC) has led to the use of disposable bioreactors and culture systems. Here, we evaluate the expansion of cord blood-derived MSC in a disposable fixed bed culture system. Starting from an initial cell density of 6.