Biologics: Targets & Therapy (Apr 2021)
Virus Neutralization by Human Intravenous Immunoglobulin Against Influenza Virus Subtypes A/H5 and A/H7
Abstract
Ritsuko Kubota-Koketsu,1,2,* Mikihiro Yunoki,3,* Yoshinobu Okuno,4 Kazuyoshi Ikuta1 1Department of Virology, Research Institute for Microbial Diseases, Osaka University, Osaka, Japan; 2Surveillance Section, Research and Production Technology Department, The Research Foundation for Microbial Diseases of Osaka University, Kagawa, Japan; 3Research and Development Division, Japan Blood Products Organization, Tokyo, Japan; 4Kanonji Institute, The Research Foundation for Microbial Diseases of Osaka University, Kagawa, Japan*These authors contributed equally to this workCorrespondence: Ritsuko Kubota-KoketsuDepartment of Viral Infections, Research Institute for Microbial Diseases, Osaka University, 3-1 Yamadaoka, Suita, Osaka, 565-0871, JapanTel +1-6-6879-8348Fax +1-6-6879-8347Email [email protected] YunokiResearch and Development Division, Japan Blood Products Organization, 15F Tamachi Station Tower N, 3-1-1 Shibaura, Minato-ku, Tokyo, 108-0023, JapanTel +81-3-6435-6500Fax +81-3-6435-6274Email [email protected]: Highly pathogenic avian influenza viruses are a threat to human health. Although donor populations have not experienced pandemic, they have been immunized by natural infections and/or vaccinations of influenza viruses such as A/H1N1, A/H3N2, and B. Therefore, it is considered that human intravenous immunoglobulin (IVIG) derived from healthy donors does not include IgG against avian influenza viruses. However, cross-reactivity has not been evaluated yet. In this study, cross-reactivity against the avian influenza virus A/H5N1, A/H7N1, A/H7N2, A/H7N7, A/H7N9, and A/H10N9 was evaluated.Materials and Methods: Several lots of IVIG derived from healthy donors in Japan were tested for virus neutralization using single- or multi-cycle virus neutralizing (S-VN or M-VN) assays that evaluate the infection-step associated with HA or the infection and propagation steps associated with HA and NA, respectively. In addition, anti-NA activities were evaluated by inhibiting the enzymatic activity in NAI assays.Results: IVIG lots showed high neutralizing activities against three A/H5N1 strains in M-VN assays, whereas activities in S-VN assays were unstable. In addition, A/H7N2 was also neutralized in S-VN and M-VN assays, with higher activity in M-VN than in S-VN assays. A/H7N1 was neutralized in S-VN and M-VN assays. In contrast, weak or no activity against A/H7N7, A/H7N9, and A/H10N9 was observed in S-VN and M-VN assays. NAI assay results show that IVIG lots had inhibitory activities against N1 and N2; however, N2 activities differed depending on the strain. In contrast, no activities were observed against N7 and N9.Conclusion: These results suggest that IVIG lots have neutralizing activity against avian influenza viruses during the virus propagation step, except for one strain, although no or weak activity was observed during the infection step.Keywords: avian influenza virus, A/H5, A/H7, neutralizing, intravenous immunoglobulin
