Virji M, Stevenson G T
Br J Cancer. 1979 Apr;39(4):434-40. doi: 10.1038/bjc.1979.77.
When L2C leukaemic B lymphocytes from guinea-pigs were incubated in vitro with antibody directed to their surface immunoglobulin (Ig), a rapid rise in intracellular adenosine 3':5'-phosphate (cyclic adenosine monophosphate, cAMP) was observed. Estimation of cAMP was by a protein-binding assay using bovine adrenal protein kinase. Increases up to 30-fold occurred within 30 seconds of incubation at 37 degrees C, to be succeeded by a fall which reached the basal level between 5 and 7 min. The response was proportional to the amount of antibody present. Cross-linking of surface Ig by the antibody was necessary, bivalent (Fab'gamma)2 from the antibody gave a rise in cAMP similar to that given by the parent molecule, whereas monomeric Fab'gamma was ineffective unless it was subsequently cross-linked by anti-antibody. The rise was too rapid to have required capping of the surface Ig for its induction. Not all perturbations of the plasma membrane by antibody induce such a surge in cAMP, since anti-beta2 microglobulin, also reacting with the lymphocyte surface, failed to alter cAMP concentration. The results emphasize that immunotherapy can be influenced by antibody altering the metabolic activity of target cells, quite apart from activation of immunological cytotoxic pathways.
当将豚鼠的L2C白血病B淋巴细胞与针对其表面免疫球蛋白（Ig）的抗体在体外孵育时，观察到细胞内3':5'-磷酸腺苷（环磷酸腺苷，cAMP）迅速升高。cAMP的测定采用使用牛肾上腺蛋白激酶的蛋白质结合测定法。在37℃孵育30秒内，cAMP增加高达30倍，随后下降，在5至7分钟之间降至基础水平。该反应与存在的抗体量成比例。抗体对表面Ig的交联是必需的，抗体的二价（Fab'γ）2引起的cAMP升高与亲本分子引起的相似，而单体Fab'γ无效，除非随后被抗抗体交联。这种升高太快，不可能是由于表面Ig的封帽诱导所致。并非抗体对质膜的所有扰动都会诱导cAMP如此激增，因为同样与淋巴细胞表面反应的抗β2微球蛋白未能改变cAMP浓度。结果强调，免疫疗法可受到改变靶细胞代谢活性的抗体的影响，这与免疫细胞毒性途径的激活完全不同。
