Snyderman R, Pike M C
Infect Immun. 1975 Feb;11(2):273-9. doi: 10.1128/iai.11.2.273-279.1975.
Complex polysaccharides and lipopolysaccharides can activate the terminal components of complement by either the classical (antibody, C1, C4, and C2) or alternative complement pathways, but the relative importance of either pathway for terminal component consumption in normal serum is poorly understood. Since classical complement pathway function requires both calcium and magnesium ions, whereas the alternative pathway requires only magnesium ions, selective chelation of calcium ions in serum can be used to block the classical complement pathway while leaving the alternative pathway intact. In these studies, ethyleneglycol-bis-(beta-aminoethyl ether)N, N-tetraacetic acid, a potent chelator or calcium, was used to block the classical complement pathway in normal guinea pig serum. Consumption of the terminal complement components by endotoxin, inulin, and zymosan in such serum was strikingly depressed when compared to serum containing an intact classical complement pathway. These studies demonstrate that in normal serum, both the classical and alternative complement pathways participate in the consumption of the terminal complement components by complex polysaccharides and lipopolysaccharides.
复杂多糖和脂多糖可通过经典途径（抗体、C1、C4和C2）或替代补体途径激活补体的终末成分，但对于正常血清中任一途径在终末成分消耗方面的相对重要性，人们了解甚少。由于经典补体途径的功能需要钙离子和镁离子，而替代途径仅需要镁离子，因此血清中钙离子的选择性螯合可用于阻断经典补体途径，同时使替代途径保持完整。在这些研究中，乙二醇双（β-氨基乙醚）N，N-四乙酸（一种有效的钙离子螯合剂）被用于阻断正常豚鼠血清中的经典补体途径。与含有完整经典补体途径的血清相比，内毒素、菊粉和酵母聚糖在此类血清中对补体终末成分的消耗显著降低。这些研究表明，在正常血清中，经典补体途径和替代补体途径均参与了复杂多糖和脂多糖对补体终末成分的消耗。
