Establishment of a Reverse Genetic System from a Bovine Derived Influenza D Virus Isolate

An Antiviral Drug-Peramivir: Degradation and Identification of Impurities and the Endorsement of an HPLC-MS Method

BACKGROUND

Peramivir is a neuraminidase inhibitor that serves as a transition state analogue for influenza neuraminidase, inhibiting the formation of new viruses in infected cells, and has been approved for intravenous administration.

OBJECTIVE

To validate an HPLC method used to identify the degraded products of the antiviral drug peramivir.

METHODS

Herein, we report the identification of compounds formed after the degradation of peramivir through acid, alkali, peroxide, thermal, and photolytic degradation. At the level of toxicology, a technique was devised for the isolation and measurement of peramivir.

RESULTS

A sensitive and reliable LC-tandem mass spectrometry technique for the quantitative measurement of Peramivir and its impurities was developed and verified in order to comply with the recommendations made by the International Council for Harmonisation (ICH). The proposed protocol was in the 50-750 µg/mL range. Relative Standard Deviation values of less than 2.0% indicated good recovery in the range of 98.36-102.57%. Within the studied range, the calibration curves demonstrated good linearity and, in addition, the fitting of correlation coefficient was more than 0.999 for every impurity. Quantitative analysis of contaminants revealed the high efficiency at a low level.

CONCLUSION

Given its ability to separate degradation products, quantitative analysis is used to detect and quantify known and unknown impurities and degradants in the peramivir drug substance during routine analysis and stability studies. No significant degradation was found in peroxide and photolytic degradation studies.

HIGHLIGHTS

An HPLC method was developed and put to the test in order to analyze the behavior of the impurities of peramivir as they degraded when subjected to the stress conditions suggested by the ICH. Peramivir was found to be stable under peroxide and photolysis conditions but not stable or degradable when exposed to the acid, base, and thermal stress conditions. The method developed was extremely precise, linear, accurate, robust, and rugged. As a result, this technology has the potential to be used in the medication production process for regular impurity analysis as well as for the stability analysis of peramivir.

Time-resolved characterization of the innate immune response in the respiratory epithelium of human, porcine, and bovine during influenza virus infection

Viral cross-species transmission is recognized to be a major threat to both human and animal health, however detailed information on determinants underlying virus host tropism and susceptibility is missing. Influenza C and D viruses (ICV, IDV) are two respiratory viruses that share up to 50% genetic similarity, and both employ 9-O-acetylated sialic acids to enter a host cell. While ICV infections are mainly restricted to humans, IDV possesses a much broader host tropism and has shown to have a zoonotic potential. This suggests that additional virus–host interactions play an important role in the distinct host spectrum of ICV and IDV. In this study, we aimed to characterize the innate immune response of the respiratory epithelium of biologically relevant host species during influenza virus infection to identify possible determinants involved in viral cross-species transmission. To this end, we performed a detailed characterization of ICV and IDV infection in primary airway epithelial cell (AEC) cultures from human, porcine, and bovine origin. We monitored virus replication kinetics, cellular and host tropism, as well as the host transcriptional response over time at distinct ambient temperatures. We observed that both ICV and IDV predominantly infect ciliated cells, independently from host and temperature. Interestingly, temperature had a profound influence on ICV replication in both porcine and bovine AEC cultures, while IDV replicated efficiently irrespective of temperature and host. Detailed time-resolved transcriptome analysis revealed both species-specific and species uniform host responses and highlighted 34 innate immune-related genes with clear virus-specific and temperature-dependent profiles. These data provide the first comprehensive insights into important common and species-specific virus-host dynamics underlying the distinct host tropism of ICV and IDV, as well as possible determinants involved in viral cross-species transmission.

Evaluation of the Glycan-Binding and Esterase Activities of Hemagglutinin-Esterase-Fusion Glycoprotein from Influenza D Virus

Influenza D virus (IDV) is a new member of influenza virus that uses cattle as the primary reservoir and infects multiple agricultural animals. Similar to influenza C virus (ICV), IDV also has seven segments in its genome and has only one major surface glycoprotein, called the hemagglutinin-esterase-fusion (HEF) protein, for receptor-binding, receptor-destroying, and membrane fusion. HEF utilizes 9-O-acetylated sialic acids as its receptor and has both receptor binding and esterase activities, thus is a critical determinant of host tropism. Here, we summarize the methods to evaluate the glycan-binding and esterase activities of HEF in vitro. The glycan-bind property is monitored through glycan microarray, MDCK cell-binding assay, Hemagglutination assay, solid-phase lectin binding assay, and immunofluorescence of tissue sections, and its esterase property is analyzed via esterase enzymatic activity assay.