Instituto de Patobiología, Centro Nacional de Investigaciones Agropecuarias, Instituto, Nacional de Tecnología Agropecuaria, Calle Las Cabañas y Los Reseros s/n, Casilla de Correo 25 (1712), Castelar, Buenos Aires, Argentina.
Toxicon. 2011 Sep 15;58(4):380-8. doi: 10.1016/j.toxicon.2011.07.009. Epub 2011 Jul 22.
Shiga toxins (Stx1 and Stx2) are the main virulence factors of enterohemorrhagic Escherichia coli (EHEC), a foodborne pathogen associated with diarrhea, hemorrhagic colitis and hemolytic uremic syndrome. The aim of this study was to evaluate the antibodies against Stx2 obtained from egg yolks of laying hens immunized with a recombinant Stx2B subunit. A high specific response in serum was observed 25 days after the first immunization and IgY antibodies were extracted from day 47th and purified from egg yolk. A concentration of 0.84 mg of total IgY/ml of egg yolk was obtained, of which 8% were antigen specific. The ability of anti-Stx2B IgY to recognize Stx2B and Stx2 either in solid-phase or in solution were evaluated and compared with anti-Stx2B rabbit antibodies by Western blotting and ELISA. The protective efficacy of IgY against Stx2 was determined by in vitro and in vivo experiments. The results show that IgY was able to recognize Stx2B and Stx2 in denatured conditions, attached to a solid-phase and free in solution. The anti-Stx2B IgY could effectively block the biological activity of Stx2 on Vero cells and protect mice from Stx2 challenge. The data suggest that immunization of hens with Stx2B could be a strategy to obtain at low cost a relatively high concentration of anti-Stx2 egg yolk IgY, able to neutralize Stx2 lethal activity. IgY technology could be an useful tool for research, diagnosis and therapy of EHEC infection.
志贺毒素（Stx1 和 Stx2）是肠出血性大肠杆菌（EHEC）的主要毒力因子，EHEC 是一种与腹泻、出血性结肠炎和溶血尿毒综合征相关的食源性病原体。本研究旨在评估用重组 Stx2B 亚单位免疫产蛋母鸡获得的针对 Stx2 的抗体。首次免疫后 25 天观察到血清中具有高特异性反应，并且从第 47 天开始从蛋黄中提取和纯化 IgY 抗体。获得了 0.84mg/ml 蛋黄总 IgY 的浓度，其中 8%为抗原特异性。通过 Western blot 和 ELISA 评估了抗 Stx2B IgY 识别固相或溶液中 Stx2B 和 Stx2 的能力，并与抗 Stx2B 兔抗体进行了比较。通过体外和体内实验确定了 IgY 对 Stx2 的保护效力。结果表明，IgY 能够在变性条件下识别 Stx2B 和 Stx2，附着在固相上并自由存在于溶液中。抗 Stx2B IgY 能够有效阻断 Stx2 在 Vero 细胞上的生物学活性，并保护小鼠免受 Stx2 攻击。数据表明，用 Stx2B 免疫母鸡可能是一种以低成本获得相对高浓度抗 Stx2 卵黄 IgY 的策略，能够中和 Stx2 的致死活性。IgY 技术可能是研究、诊断和治疗 EHEC 感染的有用工具。
