Petersson B A
Scand J Immunol. 1975;4(8):777-84. doi: 10.1111/j.1365-3083.1975.tb03717.x.
Histamine release from normal human leukocytes can be induced by anti-IgE or protein A from Staphylococcus aureus. After incubation in buffer at 37 degrees C for various time intervals or repeated washings with buffer, or both procedures, the leukocytes lose most of their reactivity to protein A, whereas the reactivity to anti-IgE is unaltered. Cells deprived of their protein A reactivity can be induced to release histamine by IgG complexed with protein A. Maximal release (23%-81%) from 0.6-1.0 times 10(7) leukocytes per ml is obtained if the mixture contains 1-2 mug protein A and 8-16 mug IgG per ml. The ratio between protein A and IgG in the most active mixtures is 1:8 or 1:16 on a weight basis, which corresponds to 2-4 IgG molecules per protein A molecule. Heat treatment does not destroy the capacity of IgG to mediate histamine release. Mixtures of protein A and the Fc part of IgG can also initiate the release. Futhermore, it is shown that the protein A-IgG mixture and anti-IgE induce cross-desensitization to each other. This indicates that, like cell-bound IgG, IgG in complex with protein A triggers partially the same reaction sequence as IgE.
抗IgE或金黄色葡萄球菌的蛋白A可诱导正常人白细胞释放组胺。在缓冲液中于37℃孵育不同时间间隔，或用缓冲液反复洗涤，或两种操作都进行后，白细胞对蛋白A的反应性大部分丧失，而对抗IgE的反应性未改变。失去对蛋白A反应性的细胞可被与蛋白A结合的IgG诱导释放组胺。如果混合物每毫升含有1 - 2微克蛋白A和8 - 16微克IgG，则每毫升0.6 - 1.0×10⁷个白细胞可获得最大释放量（23% - 81%）。在最活跃的混合物中，蛋白A与IgG的重量比为1:8或1:16，这相当于每个蛋白A分子有2 - 4个IgG分子。热处理不会破坏IgG介导组胺释放的能力。蛋白A与IgG的Fc部分的混合物也可引发释放。此外，研究表明蛋白A - IgG混合物和抗IgE会相互诱导交叉脱敏。这表明，与细胞结合的IgG一样，与蛋白A结合的IgG部分触发了与IgE相同的反应序列。
