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Kreppel, F.

Publications and source records attributed to Kreppel, F..

2 recordsLinked to original sources

Simple, low-cost, and well-performing method, the outgrowth technique, for the isolation of epithelial cells from nasal polyps

ObjectivesEpithelial cells are an important part of the pathomechanism in chronic rhinosinusitis with nasal polyps. It is therefore essential to establish a robust method for the isolation and culture of epithelial cells from nasal polyps to enable further research. In this study, the feasibility of the outgrowth technique for the isolation of the epithelial cells from the nasal polyps was evaluated. MethodsThe outgrowth technique was performed to isolate the epithelial cells. Proliferation was evaluated up to the 3rd passage. Epithelial cells were identified and differentiation and proliferation were evaluated using flow cytometry with anti-cytokeratin, anti-p63, and anti-Ki-67. A functionality test was assessed by determining type 2-relevant proteins using ELISA, representatively, interleukin-33 and periostin. ResultsUsing the outgrowth technique, epithelial cells could be isolated from all tissue samples. Isolated epithelial cells showed a proliferation rate of approximately 7- to 23-fold every 6 days up to the 3rd passage. Over 97% of isolated cells were shown to be cytokeratin- and p63-positive, and over 86% of them were Ki-67-positive in flow cytometry. Interleukin-33 and periostin were detectable in the supernatant. ConclusionsWe introduce a simple, low-cost, and well-performing method for isolating epithelial cells from nasal polyps with the outgrowth technique.

cell biology↗

Adenovirus type 34 and HVR1-deleted Adenovirus type 5 do not bind to PF4: clearing the path towards vectors without thrombosis risk

The adenoviral vector based AstraZeneca and Janssen COVID vaccines have been associated with rare cases of thrombosis, a condition which depends on adenovirus binding to the blood protein Platelet Factor 4 (PF4). In order to identify adenoviruses with low or absent affinity for PF4, we screened dozens of types from various adenovirus species, and Adenovirus type 5 (Ad5) derived vectors carrying genetic or chemical modifications of different hexon hyper-variable regions (HVR). For this purpose, we established an armamentarium of techniques including ELISA-qPCR and Aggregate Pull-Down (APD), which enabled fast and sensitive assessments of virus-protein interactions. Unlike most tested serotypes, Ad34 did not bind to PF4. Likewise, the deletion or shielding of the HVR1 loop of Ad5 seemingly ablated its PF4 binding. Therefore, we showed that PF4 binds to adenovirus hexon through interactions dependent on HVR1, and identified vectors that may avoid or decrease the risk of thrombosis and represent safer candidates for vaccine or gene therapy vector development.

microbiology↗