Merrill W W, Naegel G P, Olchowski J J, Reynolds H Y
Am Rev Respir Dis. 1985 Apr;131(4):584-7. doi: 10.1164/arrd.1985.131.4.584.
Although total concentration of immunoglobulin G has been quantitated in the lower respiratory tract of humans, the contribution of the 4 subclass species of IgG to total recoverable IgG protein has not been assessed. We have developed sensitive, micro-ELISA assays specific for the individual subclasses and employed them to measure serum and local intrapulmonary levels of these proteins. We have compared lung lavage and serum concentrations of these proteins (relative to albumin) and also compared these immunoglobulins with IgA and IgE. The results of serum level measurements of subclass proteins are similar to results reported by others; IgG1 and IgG2 are present in lung lavage in concentrations similar to their serum concentration, serum and lavage levels are directly related, and IgG4 is increased in lavage compared with that in serum, suggesting increased local synthesis or accumulation of this protein within the lower respiratory tract. Local intrapulmonary concentrations of both IgA and IgE also are increased compared with those in their serum concentrations. Local IgG3 is variable, with some subjects having increased amounts compared with that in serum, whereas others have concentrations similar to those in serum. These data suggest a preferential accumulation of IgG4 in the lower respiratory tract. It is possible that IgG4, like IgA and IgE, plays a special role in the immune defense of the lung.
尽管已对人类下呼吸道中免疫球蛋白G的总浓度进行了定量分析，但IgG的4个亚类对可回收的总IgG蛋白的贡献尚未得到评估。我们开发了针对各个亚类的灵敏的微量酶联免疫吸附测定法，并使用它们来测量这些蛋白质的血清和肺内局部水平。我们比较了这些蛋白质的肺灌洗和血清浓度（相对于白蛋白），还将这些免疫球蛋白与IgA和IgE进行了比较。亚类蛋白质血清水平测量结果与其他人报告的结果相似；IgG1和IgG2在肺灌洗中的浓度与其血清浓度相似，血清和灌洗水平直接相关，与血清相比，灌洗中的IgG4增加，表明该蛋白质在下呼吸道中的局部合成或积累增加。与血清浓度相比，肺内局部IgA和IgE的浓度也增加。局部IgG3存在差异，一些受试者与血清相比含量增加，而另一些受试者的浓度与血清相似。这些数据表明IgG4在下呼吸道中优先积累。IgG4可能像IgA和IgE一样，在肺部免疫防御中发挥特殊作用。
