接种了活减毒鼻内传染性喉气管炎疫苗的马会对 SEQ2190 和 SeM 产生血清转化。

Horses vaccinated with live attenuated intranasal strangles vaccine seroconvert to SEQ2190 and SeM.

机构信息

Department of Clinical Studies New Bolton Center, University of Pennsylvania, Kennett Square, PA, USA.

Department of Microbiology, Animal Health Trust, Kentford, Newmarket, Suffolk, UK.

出版信息

Equine Vet J. 2022 Mar;54(2):299-305. doi: 10.1111/evj.13443. Epub 2021 Mar 18.

DOI:10.1111/evj.13443

PMID:33630353

Abstract

BACKGROUND

The dual antigen iELISA uses two Streptococcus equi subsp equi surface protein antigens composed of N-terminal portions of SEQ2190 (Antigen A) and SeM (Antigen C). It is currently used to identify animals exposed to S. equi which have developed an immune response to the target antigens.

OBJECTIVES

To determine the usefulness of the dual antigen iELISA in a population of horses vaccinated with Pinnacle IN. We hypothesised that horses vaccinated for strangles with a live attenuated, non-encapsulated SeM-2 strain of S. equi, would seroconvert when tested 5 weeks later by the dual antigen iELISA.

STUDY DESIGN

Prospective case-control study.

METHODS

Three separate serum samples were obtained from 26 client-owned horses vaccinated annually with Pinnacle IN and 26 university-owned (non-vaccinates): at annual strangles vaccination (S1), 5-week post-vaccination (S2) from vaccinates, and a third (S3) (at 10 weeks) from vaccinates who received a booster. Seropositivity was defined as an OD450 nm value ≥0.5 for one or both antigens. Mixed-effects ordered logistic regression analysis was used to identify factors associated with a suspect seropositive and seropositive value on the combined Antigen A and Antigen C iELISA. Post hoc pairwise comparisons of linear predictive margins were used to assess the differences in OD450 at a specific time between Antigens A and C.

RESULTS

Nineteen of 25 (76%) vaccinates were seropositive at S2 compared to 1 of 26 (4%) non-vaccinates. When adjusted for sample number, vaccinates were more likely to be seropositive or suspect than non-vaccinates (OR 14; P = .02, 95% CI 1.62-122.03). The OD450 value was significantly larger for Antigen C than Antigen A for vaccinates (P < .001; 95% CI 0.13-0.26) when normalised by age, sex and breed.

MAIN LIMITATIONS

Guttural pouch sampling for S. equi in seroconverted horses was unavailable.

CONCLUSIONS

With a high rate of seroconversion to both antigens, the use of the dual antigen iELISA is not recommended in populations vaccinated with Pinnacle IN.

摘要

背景

双抗原 iELISA 使用两种马链球菌兽疫亚种表面蛋白抗原，由 SEQ2190（抗原 A）和 SeM（抗原 C）的 N 端组成。目前用于鉴定已对目标抗原产生免疫反应的 S. equi 暴露动物。

目的

确定双抗原 iELISA 在接种 Pinnacle IN 的马群中的有用性。我们假设，用活的、非囊泡化的 S. equi SeM-2 株弱毒疫苗接种的马，在 5 周后通过双抗原 iELISA 检测时将发生血清转化。

研究设计

前瞻性病例对照研究。

方法

从 26 匹每年接种 Pinnacle IN 的客户所有的马和 26 匹大学所有的（未接种）马中分别采集 3 份血清样本：在每年的马流感疫苗接种时（S1）、接种后 5 周（S2），以及接种后第 10 周（S3）的 26 匹接种马。血清阳性定义为抗原 A 和抗原 C 的 OD450nm 值中的一个或两个大于 0.5。使用混合效应有序逻辑回归分析确定与可疑阳性和组合抗原 A 和抗原 C iELISA 阳性值相关的因素。事后线性预测边际的成对比较用于评估在特定时间抗原 A 和 C 之间 OD450 的差异。

结果

与 26 匹非接种马中的 1 匹（4%）相比，25 匹接种马中的 19 匹（76%）在 S2 时呈血清阳性。在调整样本数量后，接种马比非接种马更有可能呈血清阳性或可疑阳性（OR 14；P = 0.02，95%CI 1.62-122.03）。接种马的抗原 C 的 OD450 值明显大于抗原 A（P < 0.001；95%CI 0.13-0.26），在正常化年龄、性别和品种后。