Bray B A
J Clin Invest. 1978 Oct;62(4):745-52. doi: 10.1172/JCI109185.
Cold-insoluble globulin (CIG), which is immunochemically indistinguishable from the fibroblast surface protein known as large external transformation-sensitive glycoprotein and fibronectin, was detected immunologically in connective tissue fractions from adult human lung. The fractions tested were (a) intact parenchyma, (b) acidic structural glycoproteins (ASG) extracted from lung parenchyma with 0.3 M acetic acid, and (c) isolated alveolar basement membrane (ABM). For comparison with ABM, preparations of human glomerular basement membrane and human trophoblast basement membrane (TBM) were tested. CIG was not detected in glomerular basement membrane but was present in large amounts in TBM. The CIG antigen could be solubilized from the parenchyma and from ABM by collagenase digestion which indicates that CIG occurs in lung connective tissue in association with collagen. Fibrinogen antigenic determinants were present in the ASG fraction, but the question of whether CIG and fibrin(ogen) are associated in lung connective tissue requires further study. When CIG was quantified by electroimmunoassay, intact lung parenchyma contained approximately equal to 0.4% CIG, ASG contained 3-4.5% CIG, ABM contained 0.1-0.9% CIG and TBM contained 1.5%-7.2% Cg. the evidence suggests that CIG is a chemical constituent of lung connective tissue matrix where it may influence the function of alveoli.
冷不溶性球蛋白（CIG）在免疫化学上与成纤维细胞表面蛋白（即大的外部转化敏感糖蛋白和纤连蛋白）无法区分，在成人肺组织的结缔组织部分中通过免疫学方法检测到。所检测的部分包括：（a）完整的实质组织；（b）用0.3M乙酸从肺实质中提取的酸性结构糖蛋白（ASG）；（c）分离的肺泡基底膜（ABM）。为了与ABM进行比较，对人肾小球基底膜和人滋养层基底膜（TBM）制剂进行了检测。在肾小球基底膜中未检测到CIG，但在TBM中大量存在。CIG抗原可通过胶原酶消化从实质组织和ABM中溶解出来，这表明CIG在肺结缔组织中与胶原相关。纤维蛋白原抗原决定簇存在于ASG部分，但CIG与纤维蛋白（原）在肺结缔组织中是否相关的问题需要进一步研究。当通过免疫电泳法对CIG进行定量时，完整的肺实质中含有约0.4%的CIG，ASG含有3 - 4.5%的CIG，ABM含有0.1 - 0.9%的CIG，TBM含有1.5% - 7.2%的Cg。证据表明CIG是肺结缔组织基质的一种化学成分，在其中可能影响肺泡的功能。
