Boonstra A, Kijlstra A
Netherlands Ophthalmic Research Institute, Amsterdam.
Curr Eye Res. 1987 Sep;6(9):1115-23. doi: 10.3109/02713688709034884.
The ironbinding protein lactoferrin is one of the main proteins in human tears. Until now no animal models are available to investigate the exact role of this protein on the ocular surface. We have therefore started investigations concerning the presence of ironbinding proteins in various laboratory animals. In this report the presence of lactoferrin and transferrin in guinea pig tears was investigated using an iron-binding assay, Ouchterlony immunodiffusion, ELISA and immunoblotting techniques. Guinea pig tears contain a weak ironbinding activity, which is markedly lower than that observed in human tears. Lactoferrin and transferrin were identified using the fact that guinea pig lactoferrin reacts with monoclonal and polyclonal anti human lactoferrin antibodies and that guinea pig serum transferrin reacts with an anti rabbit transferrin serum. SDS-PAGE and immunoblotting showed that, guinea pig lactoferrin and transferrin have a similar molecular weight of approximately 75 kD, which is however, definitely smaller than that of human lactoferrin and transferrin (80 kD). The amount of lactoferrin in guinea pig tears, measured in an ELISA using anti human lactoferrin antisera, was very low (equalling 600 mg/ml of human lactoferrin immunoreactivity). Transferrin in guinea pig tears was measured with an ELISA in 10 guinea pigs and resulted in a mean concentration of 22.3 micrograms/ml. The species comparisons performed until now indicate that human tears remain unique in their high content of lactoferrin.
铁结合蛋白乳铁蛋白是人类泪液中的主要蛋白质之一。到目前为止，尚无动物模型可用于研究该蛋白在眼表的确切作用。因此，我们开始研究各种实验动物中铁结合蛋白的存在情况。在本报告中，我们使用铁结合测定法、双向免疫扩散法、酶联免疫吸附测定法（ELISA）和免疫印迹技术，对豚鼠泪液中乳铁蛋白和转铁蛋白的存在情况进行了研究。豚鼠泪液具有较弱的铁结合活性，明显低于人类泪液中观察到的铁结合活性。利用豚鼠乳铁蛋白与单克隆和多克隆抗人乳铁蛋白抗体反应，以及豚鼠血清转铁蛋白与抗兔转铁蛋白血清反应这一事实，鉴定出了乳铁蛋白和转铁蛋白。十二烷基硫酸钠-聚丙烯酰胺凝胶电泳（SDS-PAGE）和免疫印迹显示，豚鼠乳铁蛋白和转铁蛋白的分子量相似，约为75 kDa，但肯定小于人类乳铁蛋白和转铁蛋白的分子量（80 kDa）。使用抗人乳铁蛋白抗血清通过ELISA测定，豚鼠泪液中乳铁蛋白的含量非常低（相当于600 μg/ml人乳铁蛋白免疫反应性）。在10只豚鼠中用ELISA测定了豚鼠泪液中的转铁蛋白，平均浓度为22.3 μg/ml。到目前为止进行的物种比较表明，人类泪液中乳铁蛋白的高含量仍然是独一无二的。
