Samuelsson A, Yari F, Hinkula J, Ersoy O, Norrby E, Persson M A
Karolinska Institute, Department of Medicine, Stockholm, Sweden.
Eur J Immunol. 1996 Dec;26(12):3029-34. doi: 10.1002/eji.1830261231.
Human antibodies against HIV-1 have been sought to study neutralization events on the molecular level, and for possible use in passive immune intervention. The development of phage display techniques has opened the possibility of rapidly generating human monoclonal antibodies with desired specificities. We and others have isolated human HIV-1 neutralizing antibody fragments using this technique. Bacterial expression of isolated clones does, however, differ broadly both in expression levels and functional activity. In addition, intact IgG cannot be expressed in bacteria. By transferring the genes of isolated Fab clones to a mammalian expression system we could perform a comparison of functional activity between Fab expressed in bacterial and mammalian cells, as well as Fab and whole IgG. Fab fragments expressed in mammalian cells showed increased virus neutralizing activity compared to the same Fab clones expressed in Escherichia coli, underlining the inefficiency of procaryotic expression. No difference in HIV-1 neutralizing capacity was detected between monovalent (Fab) and divalent (whole antibody) reagents expressed in CHO cells. Thus, bivalency does not always confer improved neutralization efficacy.
人们一直在寻找抗HIV-1的人类抗体，以便在分子水平上研究中和作用，并可能用于被动免疫干预。噬菌体展示技术的发展为快速产生具有所需特异性的人类单克隆抗体提供了可能性。我们和其他人已经使用这种技术分离出了人类HIV-1中和抗体片段。然而，分离克隆的细菌表达在表达水平和功能活性上都有很大差异。此外，完整的IgG不能在细菌中表达。通过将分离的Fab克隆的基因转移到哺乳动物表达系统中，我们可以比较在细菌和哺乳动物细胞中表达的Fab以及Fab和完整IgG之间的功能活性。与在大肠杆菌中表达的相同Fab克隆相比，在哺乳动物细胞中表达的Fab片段显示出更高的病毒中和活性，这突出了原核表达的低效性。在CHO细胞中表达的单价（Fab）和二价（完整抗体）试剂之间未检测到HIV-1中和能力的差异。因此，双价性并不总是能提高中和效果。
