Yang Fan, Zhu Zixiang, Liu Huanan, Cao Weijun, Zhang Wei, Wei Ting, Zheng Min, Zhang Keshan, Tian Hong, Zeng Qiaoying, Cai Xuepeng, Zheng Haixue
College of Veterinary Medicine, Gansu Agricultural University, Lanzhou 730070, China.
State Key Laboratory of Veterinary Etiological Biology, National Foot and Mouth Diseases Reference Laboratory, Key Laboratory of Animal Virology of Ministry of Agriculture, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou 730046, China.
Vaccines (Basel). 2021 Sep 24;9(10):1066. doi: 10.3390/vaccines9101066.
Senecavirus A (SVA) is a newly porcine virus that has been detected in many countries since its first detection in pigs in Canada in 2007, and it remains endemic in many countries in Asia and America, which has become a substantial problem for the pig industry. Vaccination is a potentially effective strategy for the prevention and control of SVA infection. Our lab has developed a SVA vaccine candidate previously. In this study, the antibody response to the prepared vaccine in sows and their offspring was evaluated. Vaccination of sows with inactivated SVA vaccines during pregnancy elicited SVA-specific virus-neutralizing antibodies. Vaccination with a high dose of SVA vaccine followed a booster immunization contributed to a long-term duration of the persistence of maternally derived neutralizing antibodies (MDAs) in the milk of the sows (>14 days). In contrast, vaccination with a single low dose of SVA vaccine resulted in a short-term persistence of MDAs in the milk (2-7 days). The MDAs could be efficiently transferred from the sows to their offspring through the colostrum/milk but not the umbilical cord blood. The antibody titers and the duration of the persistence of MDAs in the offspring are highly associated with the antibody levels in the milk from the sows. Vaccination of sows with a booster dose of SVA vaccine resulted in a longer-lasting MDAs in their offspring (persisted for at least 90 days). However, vaccination with the single low dose of vaccine only brought about 42 days of MDAs persistence in their offspring. The effect of MDAs on active immunization with SVA vaccine in offspring was further evaluated, which showed that vaccination of the SVA vaccine in the presence of MDAs at the titer of ≈1:64 or less could overcome the MDAs' interference and give rise to effective antibody response. This will help for establishing the optimal times and schedules for SVA vaccination in pigs.
A组赛内卡病毒（SVA）是一种新发现的猪病毒，自2007年在加拿大猪群中首次被检测到以来，已在许多国家被发现，并且在亚洲和美洲的许多国家仍然呈地方性流行，这已成为养猪业的一个重大问题。疫苗接种是预防和控制SVA感染的一种潜在有效策略。我们实验室之前已开发出一种SVA候选疫苗。在本研究中，评估了母猪及其后代对所制备疫苗的抗体反应。在怀孕期间用灭活的SVA疫苗对母猪进行接种可诱导产生SVA特异性病毒中和抗体。高剂量SVA疫苗接种后再进行加强免疫，有助于母猪乳汁中母源中和抗体（MDA）的长期持续存在（>14天）。相比之下，单次低剂量SVA疫苗接种导致乳汁中MDA的短期持续存在（2 - 7天）。MDA可通过初乳/乳汁而非脐带血有效地从母猪转移至其后代。后代中MDA的抗体滴度和持续时间与母猪乳汁中的抗体水平高度相关。用加强剂量的SVA疫苗对母猪进行接种可使其后代中的MDA持续时间更长（至少持续90天）。然而，单次低剂量疫苗接种仅使后代中的MDA持续42天。进一步评估了MDA对后代SVA疫苗主动免疫的影响，结果表明，在MDA滴度约为1:64或更低时接种SVA疫苗可克服MDA的干扰并引发有效的抗体反应。这将有助于确定猪SVA疫苗接种的最佳时间和程序。
