Painter R H, Foster D B, Gardner B, Hughes-Jones N C
Mol Immunol. 1982 Jan;19(1):127-31. doi: 10.1016/0161-5890(82)90254-1.
The functional affinity constants for Clq of subfragments if IgG1 representing the C gamma 2 (c gamma 2III) region or the whole C gamma 3 region of Fc (pFc'), have been measured by examining the ability of these fragments to inhibit the interaction between radiolabelled Clq and glutaraldehyde-treated human erythrocytes or aggregated human IgG. The value of the functional affinity constant for the C gamma 2III fragment was the same as that for Fc and that determined previously for monomeric IgG, indicating that all the elements necessary for Clq binding are contained in a single C gamma 2 domain. The pFc' fragment was inactive but a more degraded trypsin fragment from this region, at C gamma 3, showed the same affinity of binding for Clq as the C gamma 2III and Fc. These results confirm earlier findings that it is not combination of residues in the C gamma 2 which bind Clq which is responsible for their activity but their accessibility.
通过检测这些片段抑制放射性标记的Clq与戊二醛处理的人红细胞或聚集的人IgG之间相互作用的能力，已测定了代表Fc（pFc'）的Cγ2（cγ2III）区域或整个Cγ3区域的IgG1亚片段与Clq的功能亲和常数。Cγ2III片段的功能亲和常数与Fc以及先前测定的单体IgG的功能亲和常数相同，这表明Clq结合所需的所有元件都包含在单个Cγ2结构域中。pFc'片段无活性，但来自该区域Cγ3的一个降解程度更高的胰蛋白酶片段对Clq的结合亲和力与Cγ2III和Fc相同。这些结果证实了早期的发现，即与Clq结合的Cγ2中的残基组合并非其活性的原因，而是它们的可及性。
