Characterization of Immune Responses Induced by Immunization with the HA DNA Vaccines of Two Antigenically Distinctive H5N1 HPAIV Isolates

• Type of Material: Article
• Authors: Yulong Gao, Emory University; Zhiyuan Wen, Emory University; Ke Dong, Emory University; Gongxun Zhong, Chinese Academy of Agricultural Sciences; Xiaomei Wang, Chinese Academy of Agricultural Sciences; Zhigao Bu, Chinese Academy of Agricultural Sciences; Hualan Chen, Chinese Academy of Agricultural Sciences; Ling Ye, Emory University; Chinglai Yang, Emory University
• Language: English
• Date: 2012-07-31
• Publisher: Public Library of Science
• Publication Version: Final Published Version
• Copyright Statement: © 2012 Gao et al.
• License: Creative Commons Attribution 4.0 International
• Final Published Version (URL): http://dx.doi.org/10.1371%2Fjournal.pone.0041332
• Title of Journal or Parent Work: PLoS ONE
• Volume: 7
• Issue: 7
• Grant/Funding Information: This work was supported in parts by the National Natural Science Foundation of China grant 81001311 to Zhiyuan Wen, the National Natural Science Foundation of China grant 30825032 and the Chinese National Key Basic Research Program (973, 2011CB505000) to Hualan Chen, the Public Health Service grant HHSN266200700006C from the National Institutes of Health and funding from the Emory Global Health Institute to Chinglai Yang.; The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.
• Research Categories: Biology, Microbiology; Health Sciences, Immunology

Abstract

The evolution of the H5N1 highly pathogenic avian influenza virus (HPAIV) has resulted in high sequence variations and diverse antigenic properties in circulating viral isolates. We investigated immune responses induced by HA DNA vaccines of two contemporary H5N1 HPAIV isolates, A/bar-headed goose/Qinghai/3/2005 (QH) and A/chicken/Shanxi/2/2006 (SX) respectively, against the homologous as well as the heterologous virus isolate for comparison. Characterization of antibody responses induced by immunization with QH-HA and SX-HA DNA vaccines showed that the two isolates are antigenically distinctive. Interestingly, after immunization with the QH-HA DNA vaccine, subsequent boosting with the SX-HA DNA vaccine significantly augmented antibody responses against the QH isolate but only induced low levels of antibody responses against the SX isolate. Conversely, after immunization with the SX-HA DNA vaccine, subsequent boosting with the QH-HA DNA vaccine significantly augmented antibody responses against the SX isolate but only induced low levels of antibody responses against the QH isolate. In contrast to the antibody responses, cross-reactive T cell responses are readily detected between these two isolates at similar levels. These results indicate the existence of original antigenic sin (OAS) between concurrently circulating H5N1 HPAIV strains, which may need to be taken into consideration in vaccine development against the potential H5N1 HPAIV pandemic.