Novel xeno-free and serum-free culturing condition to improve piggyBac transposon-based CD19 chimeric antigen receptor T-cell production and characteristics.

BACKGROUND AIMS: Chimeric antigen receptor (CAR) T cell is a novel therapy for relapse and refractory hematologic malignancy. Characteristics of CAR T cells are associated with clinical efficacy and toxicity. The type of serum supplements used during cultivation affects the immunophenotype and function of viral-based CAR T cells. This study explores the effect of serum supplements on nonviral piggyBac transposon CAR T-cell production. METHODS: PiggyBac CD19 CAR T cells were expanded in cultured conditions containing fetal bovine serum, human AB serum or xeno-free serum replacement. We evaluated the effect of different serum supplements on cell expansion, transduction efficiency, immunophenotypes and antitumor activity. RESULTS: Xeno-free serum replacement exhibited comparable CAR surface expression, cell expansion and short-term antitumor activity compared with conventional serum supplements. However, CAR T cells cultivated with xeno-free serum replacement exhibited an increased naïve/stem cell memory population and better T-cell expansion after long-term co-culture as well as during the tumor rechallenge assay. CONCLUSIONS: Our study supports the usage of xeno-free serum replacement as an alternative source of serum supplements for piggyBac-based CAR T-cell expansion.

MicroRNA Profiles in Monocyte-Derived Macrophages Generated by Interleukin-27 and Human Serum: Identification of a Novel HIV-Inhibiting and Autophagy-Inducing MicroRNA.

Interleukin-27 (IL-27) is a pleiotropic cytokine that influences the innate and adaptive immune systems. It inhibits viral infection and regulates the expression of microRNAs (miRNAs). We recently reported that macrophages differentiated from human primary monocytes in the presence of IL-27 and human AB serum resisted human immunodeficiency virus (HIV) infection and showed significant autophagy induction. In the current study, the miRNA profiles in these cells were investigated, especially focusing on the identification of novel miRNAs regulated by IL-27-treatment. The miRNA sequencing analysis detected 38 novel miRNAs. Real-time reverse transcription polymerase chain reaction (RT-PCR) analysis confirmed that IL-27 differentially regulated the expression of 16 of the 38 miRNAs. Overexpression of the synthesized miRNA mimics by transfection revealed that miRAB40 had potent HIV-inhibiting and autophagy-inducing properties. B18R, an interferon (IFN)-neutralization protein, partially suppressed both activities, indicating that the two functions were induced via IFN-dependent and -independent pathways. Although the target mRNA(s) of miRAB40 involving in the induction of both functions was unable to identify in this study, the discovery of miRAB40, a potential HIV-inhibiting and autophagy inducing miRNA, may provide novel insights into the miRNA (small none-coding RNA)-mediated regulation of HIV inhibition and autophagy induction as an innate immune response.

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.2020.00307.].

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. Here we describe the successful use of human AB serum [10%(v/v)] as a culture supplement, as well as coating substrate for the expansion of these cells in microcarriers using (i) a spinner flask and (ii) a 500-mL mini-bioreactor (ApplikonTM Biotechnology). Cells were characterized by immunophenotype and multilineage differentiation potential. Upon an initial cell adhesion in the spinner flask of 35 ± 2.5%, culture reached a maximal cell density of 2.6 ± 0.1 × 105 at day 7, obtaining a 15 ± 1-fold increase. The implementation of the culture in the 500-mL mini-bioreactor presented an initial cell adhesion of 22 ± 5%, but it reached maximal cell density of 2.7 ± 0.4 × 105 at day 7, obtaining a 27 ± 8-fold increase. Importantly, in both stirred systems, cells retained their immunophenotype and multilineage differentiation potential (osteo-, chondro- and adipogenic lineages). Overall, the scalability of this microcarrier-based system presented herein is of major importance for the purpose of achieving clinically meaningful cell numbers.

Improving Clinical Manufacturing of IL-15 Activated Cytokine-Induced Killer (CIK) Cells.

Cytokine-induced killer (CIK) cells are an immunotherapeutic approach to combat relapse following allogeneic hematopoietic stem cell transplantation (HSCT) in acute leukemia or myelodysplastic syndrome (MDS) patients. Prompt and sequential administration of escalating cell doses improves the efficacy of CIK cell therapy without exacerbating graft vs. host disease (GVHD). This study addresses manufacturing-related issues and aimed to develop a time-, personal- and cost-saving good manufacturing process (GMP)-compliant protocol for the generation of ready-for-use therapeutic CIK cell doses starting from one unstimulated donor-derived peripheral blood (PB) or leukocytapheresis (LP) products. Culture medium with or without the addition of either AB serum, fresh frozen plasma (FFP) or platelet lysate (PL) was used for culture. Fresh and cryopreserved CIK cells were compared regarding expansion rate, viability, phenotype, and ability to inhibit leukemia growth. Cell numbers increased by a median factor of 10-fold in the presence of FFP, PL, or AB serum, whereas cultivation in FFP/PL-free or AB serum-free medium failed to promote adequate CIK cell proliferation (p < 0.01) needed to provide clinical doses of 1 × 106 T cells/kG, 5 × 106 T cells/kG, 1 × 107 T cells/kG, and 1 × 108 T cells/kG recipient body weight. CIK cells consisting of T cells, T- natural killer (T-NK) cells and a minor fraction of NK cells were not significantly modified by different medium supplements. Moreover, neither cytotoxic potential against leukemic THP-1 cells nor cell activation shown by CD25 expression were significantly influenced. Moreover, overnight and long-term cryopreservation had no significant effect on the composition of CIK cells, their phenotype or cytotoxic potential. A viability of almost 93% (range: 89-96) and 89.3% (range: 84-94) was obtained after freeze-thawing procedure and long-term storage, respectively, whereas viability was 96% (range: 90-97) in fresh CIK cells. Altogether, GMP-complaint CIK cell generation from an unstimulated donor-derived PB or LP products was feasible. Introducing FFP, which is easily accessible, into CIK cell cultures was time- and cost-saving without loss of viability and potency in a 10-12 day batch culture. The feasibility of cryopreservation enabled storage and delivery of sequential highly effective ready-for-use CIK cell doses and therefore reduced the number of manufacturing cycles.

A novel xeno-free culture system for human retinal pigment epithelium cells.

AIM: To find out an animal-free, xeno-free culture method for human fetal retinal pigment epithelium (fRPE) cells aiming for cell-replacement therapy. METHODS: Human AB serum, knock-out serum replacement (KSR) and B27 were supplemented as a substitute of fetal bovine serum (FBS) in culture medium of human fRPE cells. Cell morphology was examined by light microscope and transmission electron microscope. Proliferation ability was detected by cell cycle analysis and examination of KI67 expression. Apoptosis was analyzed using FACS. The expression of RPE-specific markers was demonstrated by quantitative real-time polymerase chain reaction (qPCR), Western blot (WB) and immunocytochemistry. Paracrine function was determined using enzyme-linked immunosorbent assay method. RESULTS: Our results indicated that the optimum concentration of KSR was 15%, the optimum concentration of B27 was 2%, and the optimum concentration of human AB serum was 10%. fRPE cells cultured in 15% KSR and 2% B27 media showed repressed propagation and differentiation ability, and gradually lost epithelial morphology and RPE function. While fRPE cells cultured in 10% human AB serum media showed a typical cobblestone morphology with pigmentation, elevated proliferation ability, satisfying paracrine function and expressed RPE-specific markers. CONCLUSION: Our study indicates that culturing fRPE cells in 10% human AB serum-supplemented medium is more favorable compared with KSR, B27 and traditional FBS-supplemented mediums when fRPE cells are to be applied in cell-based therapy.

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). The biochemical profile and quality of the produced AB HS batches were analyzed and their ability to support MSC cell growth after different storage times (0, 3, 6, 9 and 12 months) was evaluated. RESULTS: The two plasma sources used showed similar characteristics regarding biochemical constituents and quality parameters and were effective in promoting MSC growth. MSCs cultured in medium supplemented with 10% AB HS presented similar doubling times and cumulative population doublings when compared to the 10% fetal bovine serum(FBS)-supplemented culture while maintaining immunophenotype, functional features, and cytogenetic profile. CONCLUSION: Overall, the results indicate that AB HS is an efficient FBS substitute and can be used for at least 12 months after production without impairing cell proliferation and quality.

Functional analysis of dendritic cells from peripheral blood of the healthy people induced in vitro / 白血病·淋巴瘤

Objective To establish a method to induce dendritic cells (DC) from peripheral blood mononuclear cells of healthy people in normal human AB serum in vitro and to identify the phenotype and the function of DC. Methods Peripheral blood mononuclear cells (PBMNC) of healthy people were cultured in RPMI 1640 media including human AB serum, GM-CSF, rhIL-4, and/no rhCD40 for 7 days to generate DC,which were identified by morphological features, surface antigen expression and the ability to stimulate T cells.Results After cultured and induced, DC displayed typical morphology with elongated dendritic process viewed by inverse light microscope as well as Wright-Gimsa stain. Mature DC express CD83 and the costimulatory molecules CD40 CD80, and CD86 to effectively activate T cells. In the five time points of 0 day, 1st day, 3rd day, 5th day and 7th day, the expression of CD83, CD40, CD80, CD86 and CD14 were significantly different (F= 50.253, 243.769, 248.181, 191.267 and 226.339, respectively, P＜ 0.05). The ability to stimulate T cells in GM-CSF, rhIL-4, and rhCD40L group was also stronger than that in GM-CSF and rhIL-4 group. DC started to secrete IL-12 from 5th day, the values were (42.92±1.54) pg/ml and (136.18±5.27) pg/ml in group of plus CD40L and of non plus CD40L, respectively. The secretion of the two groups of IL-12 were (60.09±2.27) pg/ml and (322.30±30.60) pg/ml (t = -44.941, -22.611, bath P ＜ 0.05). There are significant differences between the two groups. Conclusion DCs can be cultured from the peripheral blood of healthy people in normal human AB and rhCD40L serum.

COMPARATIVE STUDY ON INFLUENCES OF HUMAN SERUM AND NEW BORN CALF SERUM ON IMMUNE FUNCTION OF CRYOPRESERVED LYMPHOCYTES / 中国免疫学杂志

The influences of tbe two kinds ofserum on cryopreservation of lym-phocytes was examined with respectto the functional activities of therecovered cells,and highly reco-vered and viable cells were obtainedafter cryopreservation in the mediacontaining either human AB serumor new-born calf serum,The blastTransformation of the lymphocytesfrozen withAB serum was higherthan that with new-born calf serum,while(the new-born calf serum,wasof benefit to the stability of cellmembrane Secepeors and the forma-tion of rosettes.