Pfizer Global Research and Development, Chesterfield, Missouri 63017, USA.
Protein Sci. 2010 Apr;19(4):753-62. doi: 10.1002/pro.352.
Human IgG2 antibodies may exist in at least three distinct structural isomers due to disulfide shuffling within the upper hinge region. Antibody interactions with Fc gamma receptors and the complement component C1q contribute to immune effector functions. These interactions could be impacted by the accessibility and structure of the hinge region. To examine the role structural isomers may have on effector functions, a series of cysteine to serine mutations were made on a human IgG2 backbone. We observed structural homogeneity with these mutants and mapped the locations of their disulfide bonds. Importantly, there was no observed difference in binding to any of the Fc gamma receptors or C1q between the mutants and the wild-type IgG2. However, differences were seen in the apparent binding affinity of these antibodies that were dependent on the selection of the secondary detection antibody used.
由于铰链区的二硫键重排，人源 IgG2 抗体可能存在至少三种不同的结构异构体。抗体与 Fcγ 受体和补体成分 C1q 的相互作用有助于免疫效应功能。这些相互作用可能受到铰链区的可及性和结构的影响。为了研究结构异构体对效应功能的可能作用，我们在人源 IgG2 骨架上进行了一系列半胱氨酸到丝氨酸的突变。我们观察到这些突变体具有结构均一性，并对其二硫键的位置进行了作图。重要的是，突变体与野生型 IgG2 之间在与任何 Fcγ 受体或 C1q 的结合上均未观察到差异。然而，在这些抗体的表观结合亲和力上观察到了差异，这取决于所使用的二级检测抗体的选择。
