Christian Doppler Laboratory for Innovative Immunotherapeutics, Institute of Molecular Biology, Department of Biotechnology, University of Natural Resources and Life Sciences (BOKU), Vienna, Austria.
Methods Mol Biol. 2023;2681:131-159. doi: 10.1007/978-1-0716-3279-6_9.
Antigen-binding Fc (Fcab™) fragments, where a novel antigen binding site is introduced by the mutagenesis of the C-terminal loops of the C3 domain, function as parts of bispecific IgG-like symmetrical antibodies when they replace their wild-type Fc. Their homodimeric structure typically leads to bivalent antigen binding. In particular, biological situations monovalent engagement, however, would be preferred, either for avoiding agonistic effects leading to safety issues, or the attractive option of combining a single chain (i.e., one half) of an Fcab fragment reactive with different antigens in one antibody. We present the strategies for construction and selection of yeast libraries displaying heterodimeric Fcab fragments and discuss the effects of altered thermostability of the basic Fc scaffold and novel library designs that lead to isolation of highly affine antigen binding clones.
抗原结合 Fc（FcabTM）片段，通过对 C3 结构域 C 端环的突变引入新的抗原结合位点，当取代其野生型 Fc 时，可作为双特异性 IgG 样对称抗体的一部分。它们的同源二聚体结构通常导致二价抗原结合。特别是，在某些生物学情况下，单价结合可能更受欢迎，无论是为了避免导致安全问题的激动作用，还是为了将与不同抗原反应的 Fcab 片段的单链（即一半）组合在一个抗体中的诱人选择。我们介绍了构建和选择展示异源二聚体 Fcab 片段的酵母文库的策略，并讨论了改变基本 Fc 支架的热稳定性和导致分离高亲和力抗原结合克隆的新型文库设计的影响。
