In vitro neuraminidase inhibitory concentration (IC50) of four neuraminidase inhibitors in the Japanese 2016-17 season: Comparison with the 2010-11 to 2015-16 seasons

A Lipidated Peptide with Mitochondrial Membrane Localization in Human A549 Lung Cells: From Enhanced Cell-Penetrating Properties to Biological Activity Mechanism

Here, a lipidated peptide Pal-pHK-pKV with self-assembly properties and the ability to provoke the disruption of the mitochondrial voltage-dependent anion channel-1 protein (VDAC1)-hexokinase-II (HK-II) complex is reported. The effects of the peptide pHK (N-terminal 15-amino acid fragment of HK-II that specifically binds VDAC1) are compared to those of a designed biomimetic amphiphilic pHK-pKV conjugate (pHK coupled with a cell-penetrating peptide pKV) and Pal-pHK-pKV (a lipidated conjugate modified with a hydrophobic palmitic (Pal) alkyl chain). The Pal-pHK-pKV exhibits a stronger interaction with the membrane as compared to pHK-pKV, which is demonstrated by the Langmuir-Blodgett technique and two-photon excitation microscopy. The amphiphilic peptide derivatives are cytotoxic to the A549 cells, but Pal-pHK-pKV is more cytotoxic. The inhibitory effects of the pHK derivatives on the A549 cells growth are investigated through induced apoptosis pathway, depolarized mitochondrial membrane potential, inhibited glycolysis, and activated caspase. The results of the immunofluorescence evidence the specific mitochondrial targeting by those derivatives.

The safety and efficacy of the long-acting neuraminidase inhibitor laninamivir octanoate hydrate for Inhalation Suspension Set in children under the age of 5 in a post-marketing surveillance

INTRODUCTION

We conducted a post-marketing surveillance of laninamivir octanoate hydrate for Inhalation Suspension Set in patients under the age of 5 infected with the influenza virus to evaluate safety and efficacy of the drug.

METHODS

Subjects enrolled by the centralized enrollment system were administered laninamivir once using a nebulizer based on the package insert.

RESULTS

Safety was evaluated in 1104 patients. The incidence of ADRs was 1.00% (11/1104). Compared to the incidence of ADRs of 2.04% (9/441) in the clinical trials for development, no increase in the frequency of ADRs was noted. Serious ADRs were noted in 3 patients (5 cases): 2 cases of convulsive attack, each 1 case of muscular weakness, a depressed level of consciousness, and pain in extremities. Excluding 2 patients with unknown outcomes, all of the patients recovered or their symptoms were alleviated. To detect risk factors for the occurrence of ADRs, 16 attributes were examined, and none of them were found to be significant. Efficacy was evaluated in 881 patients. The median time (95% CI) to fever resolution was 37.0 (33.0-39.0) h in type A virus (785 patients), 45.0 (34.0-56.0) h in type B virus (95 patients), and 22.0 h (1 patient) in the mixed type. This was similar to the time to fever resolution in the clinical trials.

CONCLUSION

The results of this surveillance verified that there are no noticeable problems with the safety or efficacy of laninamivir for children under the age of 5 infected with the influenza A and B viruses.

In vitro neuraminidase inhibitory concentration (IC50) of four neuraminidase inhibitors in the Japanese 2017-18 season: Comparison with the 2010-11 to 2016-17 seasons

To assess the extent of susceptibility to the four most commonly used neuraminidase inhibitors (NAIs) of the viruses epidemic in the 2017-18 Japanese influenza season, we measured the 50% inhibitory concentration (IC₅₀) for influenza virus isolates from patients and compared them with the results from the 2010-11 to 2016-17 seasons. Viral isolation was done with specimens obtained prior to treatment, and the type and subtype was determined by RT-PCR using type- and subtype-specific primers. The IC₅₀ was determined by a neuraminidase inhibition assay using a fluorescent substrate. A total of 237 virus isolates, 50 A(H1N1)pdm09, 92 A(H3N2), and 95 B were measured. No A(H1N1)pdm09 with highly reduced sensitivity for oseltamivir was found in the 2017-18 season. No isolates with highly reduced sensitivity to the four NAIs have been found for A(H3N2) or B from the 2010-11 to 2017-18 seasons. The geometric mean IC₅₀s of the four NAIs were quite consistent during the eight studied seasons. These results indicate that the sensitivity to the four commonly used NAIs has been maintained.

Consecutive influenza surveillance of neuraminidase mutations and neuraminidase inhibitor resistance in Japan

Background

The large consumption of neuraminidase inhibitors (NAIs) for the treatment of influenza virus infections places Japan at risk of becoming the epicenter of the global spread of NAI‐resistant viruses.

Objective

To clarify NA amino acid mutations of epidemic influenza viruses in Japan and their related NAI resistance.

Methods

A total of 1791 samples, including 396 A/H1N1pdm09, 1117 A/H3N2, and 278 B isolates, were collected to determine of their 50% inhibitory concentration (IC₅₀) values by NAIs (oseltamivir, zanamivir, peramivir, and laninamivir) during the Japanese seasons from 2011‐2012 to 2016‐2017. Then, 380 samples including 49 A/H1N1pdm09, 251 A/H3N2, and 80 B isolates were sequenced for the entire NA genes.

Results

Neuraminidase inhibitor‐resistant A/H1N1pdm09 viruses were detected at a frequency of 1.3% (5/396 isolates) in the epidemic seasons. None of the A/H3N2 and B viruses developed resistance to any of the four NAIs during the six seasons. Only five and 13 AA mutations were detected in the NA catalytic sites of A/H1N1pdm09 and A/H3N2 viruses, respectively. No mutations were observed in the catalytic sites of B viruses. Four of the five mutations in the catalytic sites of A/H1N1pdm09 consisted of H275Y, which was related to high resistance to oseltamivir and peramivir. Most (10/13) of the catalytic site mutations in A/H3N2 were associated with MDCK‐passaged induction (D151G/N). Finally, no mutations related to substantial NAI resistance were detected in the A/H3N2 and B viruses examined.

Conclusion

These findings suggest that the NA catalytic sites of influenza viruses are well preserved. Even in Japan, no spread of NAI‐resistant viruses has been observed, and A/H1N1pdm09 viruses carrying H275Y remain limited.

Zoonotic Potential of Influenza A Viruses: A Comprehensive Overview

Influenza A viruses (IAVs) possess a great zoonotic potential as they are able to infect different avian and mammalian animal hosts, from which they can be transmitted to humans. This is based on the ability of IAV to gradually change their genome by mutation or even reassemble their genome segments during co-infection of the host cell with different IAV strains, resulting in a high genetic diversity. Variants of circulating or newly emerging IAVs continue to trigger global health threats annually for both humans and animals. Here, we provide an introduction on IAVs, highlighting the mechanisms of viral evolution, the host spectrum, and the animal/human interface. Pathogenicity determinants of IAVs in mammals, with special emphasis on newly emerging IAVs with pandemic potential, are discussed. Finally, an overview is provided on various approaches for the prevention of human IAV infections.