Klaus G G, Vondy K, Holman M
National Institute for Medical Research, Mill Hill, London, GB.
Eur J Immunol. 1987 Dec;17(12):1787-92. doi: 10.1002/eji.1830171217.
Murine B cells were stimulated in vitro with anti-immunoglobulin (Ig) antibodies, lipopolysaccharide, or with various combinations of phorbol dibutyrate and ionomycin. Very low concentrations (ca. 10(-14) M) of cholera toxin inhibited anti-Ig-stimulated DNA synthesis, while the response to LPS was only abrogated by 2 X 10(4)-10(5)-fold greater concentrations of the toxin. Earlier responses in anti-Ig-stimulated B cells, such as increases in Ia antigen levels, were not affected by the toxin. Protein kinase C-activating phorbol esters, together with Ca2+ ionophores, are believed to stimulate DNA synthesis in lymphocytes by mimicking the two second messengers resulting from ligation of the antigen receptors. However, concentrations of cholera toxin which totally abolish anti-Ig-induced B cell proliferation significantly enhanced DNA and RNA synthesis induced by phorbol dibutyrate plus ionomycin. The results are discussed in terms of possible effects of cholera toxin on guanine nucleotide-binding (G) proteins controlling receptor coupling to second messenger-generating systems in B cells.
用抗免疫球蛋白（Ig）抗体、脂多糖或佛波醇二丁酸酯和离子霉素的各种组合在体外刺激小鼠B细胞。极低浓度（约10^(-14) M）的霍乱毒素可抑制抗Ig刺激的DNA合成，而对脂多糖的反应仅在毒素浓度高出2×10^4 - 10^5倍时才被消除。抗Ig刺激的B细胞中较早出现的反应，如Ia抗原水平的升高，不受毒素影响。蛋白激酶C激活剂佛波醇酯与Ca2+离子载体一起，被认为通过模拟抗原受体连接产生的两种第二信使来刺激淋巴细胞中的DNA合成。然而，完全消除抗Ig诱导的B细胞增殖的霍乱毒素浓度却显著增强了佛波醇二丁酸酯加离子霉素诱导的DNA和RNA合成。本文从霍乱毒素对控制B细胞中受体与第二信使生成系统偶联的鸟嘌呤核苷酸结合（G）蛋白的可能影响方面对结果进行了讨论。
