Equine Research Institute, Japan Racing Association, Tochigi, Japan.
Hidaka Training and Research Center, Japan Racing Association, Hokkaido, Japan.
J Equine Vet Sci. 2022 Feb;109:103860. doi: 10.1016/j.jevs.2021.103860. Epub 2021 Dec 29.
Updating vaccine strains is important to control equine influenza (EI). Previously, we reported that a monovalent inactivated EI vaccine derived from a virus generated by reverse genetics (RG) elicited immunogenicity in horses. In the present study, we compared antibody responses to a bivalent inactivated EI vaccine generated by RG and a commercially available bivalent inactivated EI (CO) vaccine derived from wild-type equine influenza viruses in Thoroughbred horses. The CO vaccine contained A/equine/Ibaraki/1/2007 (Florida sub-lineage clade 1) and A/equine/Yokohama/aq13/2010 (Florida sub-lineage clade 2) as vaccine strains. We generated two RG viruses possessing the hemagglutinin and neuraminidase genes from A/equine/Ibaraki/1/2007 or A/equine/Yokohama/aq13/2010. These viruses were inactivated by formalin, and the hemagglutinin titer of the RG vaccine was adjusted to be the same as that of the CO vaccine. Sixteen unvaccinated yearlings (7 for the RG vaccine group and 9 for the CO vaccine group) received two doses of a primary vaccination course four weeks apart. Thirty-two vaccinated adult horses (18 in the RG-vaccinated group and 14 in the CO vaccine group) received a single dose of a booster vaccination. The patterns of hemagglutination inhibition antibody response to the primary and booster vaccinations were similar for the RG and CO groups in unvaccinated yearlings and vaccinated adult horses. These results suggest that a bivalent vaccine derived from RG viruses elicits equivalent immunogenicity to that elicited by a CO vaccine derived from wild-type viruses. RG viruses can, therefore, be used in multivalent as well as monovalent vaccines for horses.
更新疫苗株对于控制马流感（EI）非常重要。此前，我们报道了一种由反向遗传学（RG）产生的单价灭活马流感疫苗在马中具有免疫原性。在本研究中，我们比较了 RG 产生的二价灭活马流感疫苗和源自野生型马流感病毒的市售二价灭活马流感（CO）疫苗在纯血马中的抗体反应。CO 疫苗含有 A/equine/Ibaraki/1/2007（佛罗里达亚系分支 1）和 A/equine/Yokohama/aq13/2010（佛罗里达亚系分支 2）作为疫苗株。我们生成了两种 RG 病毒，它们的血凝素和神经氨酸酶基因来自 A/equine/Ibaraki/1/2007 或 A/equine/Yokohama/aq13/2010。这些病毒用福尔马林灭活，RG 疫苗的血凝素效价调整为与 CO 疫苗相同。16 头未接种的一岁马（7 头用于 RG 疫苗组，9 头用于 CO 疫苗组）接受了两剂基础免疫，间隔四周。32 头接种过疫苗的成年马（18 头在 RG 疫苗组，14 头在 CO 疫苗组）接受了一剂加强免疫。在未接种的一岁马和接种过的成年马中，RG 和 CO 组的基础免疫和加强免疫的血凝抑制抗体反应模式相似。这些结果表明，源自 RG 病毒的二价疫苗可引起与源自野生型病毒的 CO 疫苗相当的免疫原性。因此，RG 病毒可用于马的多价和单价疫苗。
