Ringdén O
Eur J Immunol. 1978 Jan;8(1):47-52. doi: 10.1002/eji.1830080110.
Protein A from Staphylococcus aureus, in soluble form or coupled to Sepharose beads, acts as a polyclonal B cell activator (PBA) for human lymphocytes in blood and spleen. PBA activity was demonstrated in spleen cells by the ability of protein A to induce the formation of intracellular immunoglobulin synthesis and to activate polyclonal antibody secretion demonstrated against fluorescein isothiocyanate-coupled sheep erythrocytes in a modified hemolysis in gel assay. More plaqueforming cells (PFC) were seen in unseparated cells than in purified B cells. In blood lymphocytes, only few PFC were activated by soluble protein A. Protein A increased DNA synthesis in blood and spleen cells. At a concentration of 100 microgram/ml the peak response was on day 4 or 5, but at 1 microgram/ml the peak response occurred later. On day 4 of culture, high mitogenic activity was seen in unseparated lymphocytes or mixtures of separated B and T cells, whereas in enriched B and T cell suspensions activity was low. On day 7, however, DNA synthesis in both the enriched B and T cells was higher than in mixtures of B and T cells. Protein A stimulated DNA synthesis in thymus cells with a peak response on day 6. It is concluded that protein A alone or as an IgG complex can activate both B and T cells, though the mechanism of activation is not known and may be different for B and T cells.
来自金黄色葡萄球菌的蛋白A，无论是可溶形式还是偶联到琼脂糖珠上，都可作为血液和脾脏中人类淋巴细胞的多克隆B细胞激活剂（PBA）。通过蛋白A诱导细胞内免疫球蛋白合成形成以及激活针对异硫氰酸荧光素偶联绵羊红细胞的多克隆抗体分泌的能力，在改良的凝胶溶血试验中证实了脾脏细胞中的PBA活性。在未分离的细胞中比在纯化的B细胞中观察到更多的空斑形成细胞（PFC）。在血液淋巴细胞中，可溶性蛋白A仅激活了少数PFC。蛋白A增加了血液和脾脏细胞中的DNA合成。在浓度为100微克/毫升时，峰值反应出现在第4天或第5天，但在1微克/毫升时，峰值反应出现得较晚。在培养的第4天，未分离的淋巴细胞或分离的B细胞与T细胞的混合物中可见高促有丝分裂活性，而在富集的B细胞和T细胞悬液中活性较低。然而，在第7天，富集的B细胞和T细胞中的DNA合成均高于B细胞与T细胞的混合物。蛋白A刺激胸腺细胞中的DNA合成，峰值反应出现在第6天。得出的结论是，单独的蛋白A或作为IgG复合物均可激活B细胞和T细胞，尽管激活机制尚不清楚，且可能因B细胞和T细胞而异。
