The risk of microbial contamination of cellular products can be reduced when cultured in the presence of antibiotics. This however, may impact the sensitivity of microbiological tests. Given that the addition of antibiotics to cell/tissue products does not guarantee sterility but may just reduce the proliferation rate of microorganisms, microbiological testing of medicinal products remains obligatory. Thus, an appropriate method to test for microbial contamination of antibiotic-containing products has to be validated.
In the context of microbiological testing of a cellular advance therapy medicinal product, the method was validated and approved by German competent authorities for four different matrices with three matrices containing antibiotics. The paper shall provide help for establishing test methods for other investigational medicinal products which contain antibiotics.
Matrices were spiked individually with Staphylococcus aureus, Bacillus subtilis, Pseudomonas aeruginosa, Streptococcus pyogenes, Escherichia coli, Clostridium sporogenes, Propionibacterium acnes, Candida albicans, and Aspergillus brasiliensis. Samples were pretreated with penicillinase for 1 h before inoculation and incubation in BacT/ALERT iFA Plus and iFN Plus culture bottles using 3D BacT/ALERT automates. Microorganisms within positive BacT/ALERT bottles were specified. The procedure was performed in two different laboratories to prove robustness of test.
All nine tested microorganisms were detected within 14 days of incubation in accordance with requirements of the European Pharmacopoiea in terms of sensitivity, specificity and robustness of the test. Penicillin and streptomycin did not have any influence on specifications defined within the investigational medicinal product dossier.
Culturing cellular products in the presence of antibiotics can serve as an effective method to reduce contamination risk but only if the chosen antibiotics neither have any influence on specifications of the investigational medicinal product nor interfere with microbiological tests. Consequently, cells and tissues primarily contaminated with microorganisms, like placenta, may be considered as a source of cellular therapeutics when cultured for a sufficient time with antibiotics and tested with a validated method. The choice of microorganisms for the validation of the microbiological test should always consider all conceivable scenarios and should not be reduced to minimal criteria defined in European Pharmacopoiea, wrongfully believing to thus save time and effort.
Copyright © 2019 by S. Karger AG, Basel.

Th17 cells play a critical role in several autoimmune diseases, including psoriasis and psoriatic arthritis (PsA). Psoriasis is a chronic inflammatory skin disease associated with systemic inflammation and comorbidities, such as PsA. PsA develops in nearly 70% of patients with psoriasis, and osteoclasts associated bone erosion is a hallmark of the disease. Thus far, the effect of Th17 cells on osteoclastogenesis via direct cell-to-cell interactions is less understood. In this study, we observed that Th17 cells directly promote osteoclast differentiation and maturation via expression of receptor activator of nuclear factor-κ β ligand (RANKL) in vitro. We investigated the impact of conditioned medium obtained from human palatine tonsil-derived mesenchymal stem cells (T-CM) on the interactions between osteoclasts and Th17 cells. T-CM effectively blunted the RANK-RANKL interaction between the osteoclast precursor cell line RAW 264.7 and Th17 cells via osteoprotegerin (OPG) activity. The frequency of tartrate-resistant acid phosphatase (TRAP)-positive cells in the bone marrow of an imiquimod (IMQ)-induced psoriasis mouse model was decreased following T-CM injection. Therefore, our data provide novel insight into the therapeutic potential of tonsil-derived mesenchymal stem cell-mediated therapy (via OPG production) for the treatment of pathophysiologic processes induced by osteoclasts under chronic inflammatory conditions such as psoriasis.

Increased numbers of bone marrow-derived progenitor cells, known as fibrocytes, populate the peripheral circulation, orbit, and thyroid of patients with Graves' disease (GD). These cells have been implicated in the development of thyroid-associated ophthalmopathy. They can differentiate into myofibroblasts or adipocytes, produce inflammatory cytokines, and remodel tissue. This study sought to determine whether thyrotropin (TSH) and CD40 ligand (CD40L), implicated in the pathogenesis of GD, induce interleukin-12 (IL-12) in human fibrocytes.
IL-12 protein concentrations and mRNA levels were measured by Luminex and real-time polymerase chain reaction, respectively. Flow cytometry assessed intracellular IL-12 concentrations. Vector containing IL-12p40 promoter was transfected into cultured fibrocytes, and promoter activity was monitored using luciferase assay.
TSH and CD40L stimulated intracellular IL-12 protein accumulation in peripheral blood fibrocytes. Inhibiting Akt and nuclear factor-κB (NF-κB) activity diminished IL-12 expression in fibrocytes, while TSH did not induce promoter activity. TSH-mediated IL-12 production required de novo synthesized proteins and augmented IL-12 mRNA stability. IL-12 production mediated by CD40L required tumor necrosis factor receptor-associated factor 6.
TSH and CD40L induce IL-12 expression in fibrocytes, and Akt and NF-κB mediate this activity. Given the importance of IL-12 in immune function, its production by fibrocytes may promote an inflammatory immune response and tissue remodeling in thyroid-associated ophthalmopathy.

Mouse models have provided key insight into the cellular and molecular control of human immune system function. However, recent data indicate that extrapolating the functional capabilities of the murine immune system into humans can be misleading. Since immune cells significantly affect neuron survival and axon growth and also are required to defend the body against infection, it is important to determine the pathophysiological significance of spinal cord injury (SCI)-induced changes in human immune system function. Research projects using monkeys or humans would be ideal; however, logistical and ethical barriers preclude detailed mechanistic studies in either species. Humanized mice, i.e., immunocompromised mice reconstituted with human immune cells, can help overcome these barriers and can be applied in various experimental conditions that are of interest to the SCI community. Specifically, newborn NOD-SCID-IL2rg(null) (NSG) mice engrafted with human CD34(+) hematopoietic stem cells develop normally without neurological impairment. In this report, new data show that when mice with human immune systems receive a clinically-relevant spinal contusion injury, spontaneous functional recovery is indistinguishable from that achieved after SCI using conventional inbred mouse strains. Moreover, using routine immunohistochemical and flow cytometry techniques, one can easily phenotype circulating human immune cells and document the composition and distribution of these cells in the injured spinal cord. Lesion pathology in humanized mice is typical of mouse contusion injuries, producing a centralized lesion epicenter that becomes occupied by phagocytic macrophages and lymphocytes and enclosed by a dense astrocytic scar. Specific human immune cell types, including three distinct subsets of human monocytes, were readily detected in the blood, spleen and liver. Future studies that aim to understand the functional consequences of manipulating the neuro-immune axis after SCI should consider using the humanized mouse model. Humanized mice represent a powerful tool for improving the translational value of pre-clinical SCI data.
Copyright © 2015 Elsevier Inc. All rights reserved.

Fibrocytes (FC) are bone marrow-derived progenitor cells that are more abundant and infiltrate the thyroid and orbit in Graves orbitopathy (GO). FCs express high levels of thyrotropin receptor (TSHR) and insulin-like growth factor-1 receptor (IGF-1R). These receptors are physically and functionally associated, but their role in GO pathogenesis is not fully delineated. Treatment of FCs with thyroid stimulating hormone (TSH) or M22 (activating antibody to TSHR) induces the production of numerous cytokines, including tumor necrosis factor α (TNFα). Teprotumumab (TMB) is a human monoclonal IGF-1R blocking antibody currently in clinical trial for GO and inhibits TSHR-mediated actions in FCs.
To characterize the molecular mechanisms underlying TSH-induced TNFα production by FCs, and the role of IGF-1R blockade by TMB.
FCs from healthy and GD patients were treated with combinations of TSH, M22, MG132 and AKTi (inhibitors of NF-κB and Akt, respectively), and TMB. TNFα protein production was measured by Luminex and flow cytometry. Messenger RNA expression was quantified by real time PCR.
Treatment with TSH/M22 induced TNFα protein and mRNA production by FCs, both of which were reduced when FCs were pretreated with MG132 and AKTi (p<0.0001). TMB decreased TSH-induced TNFα protein production in circulating FCs from mean fluorescent index (MFI) value of 2.92 to 1.91, and mRNA expression in cultured FCs from 141- to 52-fold expression (p<0.0001). TMB also decreased M22-induced TNFα protein production from MFI of 1.67 to 1.12, and mRNA expression from 6- to 3-fold expression (p<0.0001).
TSH/M22 stimulates FC production of TNFα mRNA and protein. This process involves the transcription factor NF-κB and its regulator Akt. Blocking IGF-1R attenuates TSH/M22-induced TNFα production. This further delineates the interaction of TSHR and IGF1-R signaling pathways. By modulating the proinflammatory properties of FCs such as TNFα production, TMB may be a promising therapeutic agent for GO.