A Novel Strain of Porcine Adenovirus Detected in Urinary Bladder Urothelial Cell Culture

Urška Jerman,Mateja Kreft,Peter Veranič,Andrej Steyer,Marko Kolenc,Mateja Prijatelj

doi:10.3390/v6062505

Abstract

Contamination of cell cultures is the most common problem encountered in cell culture laboratories. Besides the secondary cell contaminations often occurring in the cell laboratories, the contaminations originating from donor animal or human tissue are equally as common, but usually harder to recognize and as such require special attention. The present study describes the detection of porcine adenovirus (PAdV), strain PAdV-SVN1 in cultures of normal porcine urothelial (NPU) cells isolated from urinary bladders of domestic pigs. NPU cell cultures were evaluated by light microscopy (LM), polymerase chain reaction (PCR), and additionally assessed by transmission electron microscopy (TEM). Characteristic ultrastructure of virions revealed the infection with adenovirus. The adenoviral contamination was further identified by the sequence analysis, which showed the highest similarity to recently described PAdV strain PAdV-WI. Additionally, the cell ultrastructural analysis confirmed the life-cycle characteristic for adenoviruses. To closely mimic the in vivo situation, the majority of research on in vitro models uses cell cultures isolated from human or animal tissue and their subsequent passages. Since the donor tissue could be a potential source of contamination, the microbiological screening of the excised tissue and harvested cell cultures is highly recommended.

Highlights

Cell cultures have become indispensable tools for biological and medical research
Contamination with bacteria or fungi usually causes visible effects on cell cultures, viruses are on the contrary, due to their small size and lack of visual cues of their presence, difficult to detect by routine light microscopy (LM) and might be overlooked [1]
Primary and the first passages of secondary normal porcine urothelial (NPU) cells seeded onto culture tissue flasks had epithelial-like morphology, as expected (Figure 1A)

Summary

Introduction

Cell cultures have become indispensable tools for biological and medical research. Advances in cell culture and development of various in vitro models have found a number of applications in studying tissue development and function in health and disease. Handling with cell cultures always poses the risk of contamination, either with eukaryotic cells from other cell cultures or, more frequently, with microbiological organisms including fungi and bacteria, and sometimes with persistent viral infections. Contamination with bacteria or fungi usually causes visible effects on cell cultures, viruses are on the contrary, due to their small size and lack of visual cues of their presence, difficult to detect by routine light microscopy (LM) and might be overlooked [1]. Contamination with viruses remains unrecognized, unless viral infection leads to cytopathological changes of the cultured cells, such as atypical cell morphology or increased cell death. The cell culture laboratory environment, the personnel or rarely already contaminated cell lines could be the source of viruses. Most commonly, the viral infection originates from infected donor animals, either by serum or when using an animal tissue as a source of cells for primary and subsequent cell cultures [1]

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Results

Conclusion