State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing 100071, China.
Int Immunopharmacol. 2011 Dec;11(12):2000-6. doi: 10.1016/j.intimp.2011.08.011. Epub 2011 Sep 7.
Highly pathogenic avian influenza H5N1 virus (HPAI H5N1) has the potential to cause a new pandemic, which may lead to disasters in the world. However, we cannot predict the HPAI H5N1 strain that might cause the pandemic. Therefore, broad-spectrum prophylactic or therapeutic preparations for containment of a possible future pandemic are urgently needed. Polyvalent equine immunoglobulin F(ab')2 may be a promising candidate.
We prepared four pepsin digested immunoglobulin F(ab')2 from the horses immunized with purified VNH5N1-Puerto Rico/8/34 (PR8)/CDC-RG (VNRG, Clade 1), A/Indonesia/05/2005(H5N1)-PR8-IBCDC-RG2 (INRG, Clade 2.1), and A/Anhui/01/2005(H5N1)-PR8-IBCDC-RG5 (AHRG, Clade 2.3.4) and PBS (negative control), respectively. The protective effect of the monovalent or polyvalent F(ab')2 against A/Ostrich/SZ/097/04 (clade 0) infection was determined by cytopathic effect (CPE) in cultured Madin-Darby canine kidney (MDCK) cells. The prophylactic and therapeutic efficacy of the polyvalent F(ab')2 was further evaluated by observing survival, weight loss and viral load when the polyvalent F(ab')2 was introduced into mice one day prior to-, three days post-lethal challenge with A/Ostrich/SZ/097/04.
The half neutralization doses (ND50) of purified monovalent equine F(ab')2 prepared by the VNRG, INRG or AHRG-immunized horses and polyvalent one against A/Ostrich/SZ/097/04 were 320, 1280, 1280 and 2560 in cultured MDCK cells, respectively. 10 μg polyvalent F(ab')2 could completely protect mice infected with 100 half lethal doses (LD50) of A/Ostrich/SZ/097/04 in preventive settings. In therapeutic settings, even when injected three days post lethal infection, mice were still completely protected, although 200 μg of polyvalent F(ab')2 was required.
Our work has provided experimental supports for testing the broad-spectrum protective efficacy of polyvalent equine immunoglobulin F(ab')2 for the future large trials.
高致病性禽流感 H5N1 病毒（HPAI H5N1）有可能引发新的大流行，这可能给全球带来灾难。然而，我们无法预测可能引发大流行的 HPAI H5N1 毒株。因此，迫切需要广谱的预防性或治疗性制剂来控制未来可能发生的大流行。多价马免疫球蛋白 F(ab')2 可能是一种很有前途的候选药物。
我们用纯化的 VNH5N1-Puerto Rico/8/34（PR8）/CDC-RG（VNRG，Clade 1）、A/Indonesia/05/2005（H5N1）-PR8-IBCDC-RG（INRG，Clade 2.1）和 A/Anhui/01/2005（H5N1）-PR8-IBCDC-RG5（AHRG，Clade 2.3.4）免疫的马制备了四种胃蛋白酶消化的免疫球蛋白 F(ab')2，以及 PBS（阴性对照）。通过细胞病变效应（CPE）在培养的 Madin-Darby 犬肾（MDCK）细胞中确定单价或多价 F(ab')2 对 A/Ostrich/SZ/097/04（Clade 0）感染的保护作用。通过观察多价 F(ab')2 引入感染 A/Ostrich/SZ/097/04 致死剂量后 1 天和 3 天的存活、体重减轻和病毒载量，进一步评估多价 F(ab')2 的预防和治疗效果。
用 VNRG、INRG 或 AHRG 免疫的马制备的纯化单价马免疫球蛋白 F(ab')2 和多价 F(ab')2 对 A/Ostrich/SZ/097/04 的半中和剂量（ND50）分别为 320、1280、1280 和 2560。10 μg 多价 F(ab')2 可完全预防 100 倍半致死剂量（LD50）A/Ostrich/SZ/097/04 感染的小鼠。在治疗性设置中，即使在感染致死剂量后 3 天注射，也能完全保护小鼠，尽管需要 200 μg 的多价 F(ab')2。
我们的工作为未来的大样本试验提供了多价马免疫球蛋白 F(ab')2 的广谱保护效果的实验支持。
