CONSTANT DOMAIN MODULATION OF ANTIBODY ACTIVITY

本提案的主要目的是阐明 对于Fc区依赖性， 抗体与抗原的协同结合。此外，我们将 表征IgG亚类相关的其他功能差异 特性.实验方法将采用划定 下面 首先，表达不同免疫球蛋白的IgG抗体的功能亲和力是不同的。 重链恒定结构域将相对于不同的 （特别是关于表位间隔）抗原的形式， 各种条件（例如，温度或离子强度）。单克隆 不同IgG亚类的抗体（mAb），但表达相同， 或相当的可变域将用于这些研究。 第二，γ 3 Fc区中参与免疫调节的位点， 协同结合将通过血清学和电子显微镜绘制 方法. 第三，将比较鼠IgG亚类与 链球菌感染小鼠模型中的清除和保护作用 肺炎。 第四，将选择具有新结合表型的mAb， 特征，以及赋予抗体 将评价协同结合的能力。 这些研究应该有助于理解功能性 IgG亚类之间的差异，特别是在抗- 细菌和抗多糖抗体应答。此外，由 增加了我们对抗体与 恒定结构域结构和功能，这些研究应该表明 改变抗体结构以增强所需功能的新方法 特性.

The major objectives of this proposal are to clarify the molecular basis for, and the significance and generality of, Fc region-dependent, cooperative binding of antibodies to antigen. In addition, we will characterize IgG subclass-associated difference in other functional properties. The experimental approaches to be employed are delineated below. First, the functional affinities of IgG antibodies expressing different heavy chain constant domains will be compared with respect to different (particularly with regard to epitope spacing) forms of antigen under a variety of conditions (e.g., temperature or ionic strength). Monoclonal antibodies (mAbs) of different IgG subclasses, but expressing identical, or comparable, variable domains will be used for these studies. Second, the sites in the gamma 3 Fc region that are involved in cooperative binding will be mapped by serologic and electron microscopic methods. Third, the murine IgG subclasses will be compared with respect to clearance and protection in a murine model infection with Streptococcus pneumoniae. Forth, mAbs with novel binding phenotypes will be selected and characterized, and new strategies for endowing antibodies with the ability to bind cooperatively will be evaluated. These studies should contribute to an understanding of the functional differences among IgG subclasses, particularly in the contexts of anti- bacterial and anti-polysaccharide antibody responses. Further more, by increasing our understanding of the relationships between antibody constant domain structure and function, these studies should suggest novel ways to alter antibody structure to enhance desired functional properties.