Laboratory of Virology, Department of Translational Physiology, Infectiology and Public Health, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, 9820 Merelbeke, Belgium.
Laboratory of Veterinary Pathology, Department of Pathobiology, Pharmacology and Zoological Medicine, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, 9820 Merelbeke, Belgium.
Vaccine. 2022 Apr 26;40(19):2723-2732. doi: 10.1016/j.vaccine.2022.03.051. Epub 2022 Mar 30.
Control of swine influenza A virus (swIAV) in North America and Europe is complicated because multiple antigenically distinct swIAV strains co-circulate in the field, and no vaccine is available that can provide broad cross-protection against all these swIAVs. In 2017, the first live attenuated influenza vaccine (LAIV) for swine was licensed in the US. The non-structural protein 1 (NS1)-truncated cluster I H3N2 strain A/swine/Texas/4199-2/98 NS1del126 (TX98 LAIV) in this vaccine provides partial cross-protection against heterologous North American cluster II and IV H3N2 swIAV strains. Its efficacy against European or more recent North American H3N2 lineages remains to be investigated. In this study, we evaluated the level of cross-protection against heterologous IAVs representative of the major H3N2 swIAV lineages in Europe and North America. TX98 LAIV prevented both nasal shedding and replication in the lungs of a North American cluster IV H3N2 swIAV for 2/4 pigs, prevented considerable nasal shedding of a North American novel human-like H3N2 swIAV for 2/4 pigs, and reduced replication of a European H3N2 swIAV in the lower respiratory tract to minimal titers for 1/3 pigs. Although TX98 LAIV elicited neutralizing antibodies against the homologous virus in serum and to a lesser extent in nose and lungs, no significant cross-reactive antibody titers against the heterologous swIAVs were detected. Partial cross-protection therefore likely relies on cellular and mucosal immune responses against conserved parts of the swIAV proteins. Since TX98 LAIV can offer partial protection against a broad range of H3N2 swIAVs, it might be a suitable priming vaccine for use in a heterologous prime-boost vaccination strategy.
北美和欧洲对甲型猪流感病毒(swIAV)的控制较为复杂,因为在野外有多种抗原不同的 swIAV 株共同传播,而且没有可提供广泛交叉保护的疫苗来预防所有这些 swIAV。2017 年,美国批准了首个用于猪的减毒活流感疫苗(LAIV)。该疫苗中的非结构蛋白 1(NS1)截断的 I 型血凝素(H3N2)株 A/swine/Texas/4199-2/98 NS1del126(TX98 LAIV)可提供针对异源北美 II 型和 IV 型 H3N2 swIAV 株的部分交叉保护。但其对欧洲或更新的北美 H3N2 谱系的功效仍有待研究。在这项研究中,我们评估了针对代表欧洲和北美的主要 H3N2 swIAV 谱系的异源 IAV 的交叉保护水平。TX98 LAIV 预防了 4 头猪中的 2 头北美 IV 型 H3N2 swIAV 的鼻内排毒和肺部复制,预防了 4 头猪中的 2 头北美新型类似人的 H3N2 swIAV 的大量鼻内排毒,并将 3 头猪中的 1 头的欧洲 H3N2 swIAV 在呼吸道的复制降低到最小滴度。尽管 TX98 LAIV 在血清中引发了针对同源病毒的中和抗体,并且在一定程度上在鼻子和肺部中引发了中和抗体,但未检测到针对异源 swIAV 的显著交叉反应性抗体滴度。因此,部分交叉保护可能依赖于针对 swIAV 蛋白保守部分的细胞和粘膜免疫反应。由于 TX98 LAIV 可对广泛的 H3N2 swIAV 提供部分保护,因此它可能是一种适合用于异源初免-加强免疫接种策略的基础疫苗。
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