Liang M, Chu Y K, Schmaljohn C
Virology Division, United States Army Medical Research Institute of Infectious Diseases, Fort Detrick, Frederick, Maryland 21702-5011, USA.
Virology. 1996 Mar 1;217(1):262-71. doi: 10.1006/viro.1996.0113.
We amplified by polymerase chain reaction the heavy and light chain antibody genes of two mouse hybridomas secreting neutralizing monoclonal antibodies (MAbs) to the G1 or G2 envelope proteins of Hantaan virus, cloned them into the phagemid vector pComb3, and expressed them in bacteria to yield Fab fragments. Expressed Fab fragments had the same antigenic specificities for Hantaan and Seoul viruses as the complete parent MAbs and were able to neutralize Hantaan virus in plaque-reduction neutralization assays. The authentic MAb to G2 (HCO2) could passively protect hamsters from challenge with Hantaan virus when neutralizing antibody titers of at least 1:10 were detected in the animals' sera just prior to challenge. In contrast, although 1:10 neutralization titers were also detected in hamsters receiving passively transferred, Escherichia coli-expressed HCO2 Fab, these animals were not protected from infection with Hantaan virus. Similarly, passive transfer of the HCO2 Mab on Days 1 through 4 after infection prevented antigen deposition in hamster lungs and kidneys but passive transfer of the recombinant HCO2 Fab did not. The results suggest that although neutralization by IgG antibodies correlates with protection in hamsters, the same may not be true for neutralizing Fab fragments.
我们通过聚合酶链反应扩增了两种小鼠杂交瘤的重链和轻链抗体基因，这两种杂交瘤分泌针对汉坦病毒G1或G2包膜蛋白的中和单克隆抗体（MAb），将它们克隆到噬菌粒载体pComb3中，并在细菌中表达以产生Fab片段。表达的Fab片段对汉坦病毒和汉城病毒具有与完整亲本单克隆抗体相同的抗原特异性，并且能够在蚀斑减少中和试验中中和汉坦病毒。当在攻击前动物血清中检测到至少1:10的中和抗体滴度时，针对G2的正宗单克隆抗体（HCO2）可以被动保护仓鼠免受汉坦病毒攻击。相比之下，尽管在接受被动转移的大肠杆菌表达的HCO2 Fab的仓鼠中也检测到1:10的中和滴度，但这些动物并未免受汉坦病毒感染。同样，在感染后第1天至第4天被动转移HCO2单克隆抗体可防止抗原沉积在仓鼠肺和肾中，但重组HCO2 Fab的被动转移则不能。结果表明，尽管IgG抗体的中和作用与仓鼠的保护作用相关，但中和Fab片段可能并非如此。
