Tschopp J, Masson D, Schäfer S
J Immunol. 1986 Sep 15;137(6):1950-3.
Cytoplasmic granules isolated from cytolytic T lymphocytes (CTL) lyse red blood cells or tumor cell lines in a nonspecific manner. The activity of highly purified granules was inhibited by human or rabbit serum at dilutions as high as 1/10,000. The main inhibitory activity of human serum was isolated by chromatography and was determined to be high density lipoprotein (HDL). HDL not only inhibited at a concentration of 70 ng/ml the lytic activity of isolated granules, but also of the purified, pore-forming protein perforin present in the granules. Purified low density lipoprotein was equally active. Because the CTL granule activity was inhibited by pure egg lecithin vesicles at a concentration equivalent to the phospholipid content of lipoproteins, the lipid portion of lipoproteins is the likely candidate for granule inactivation. Lipoproteins also decreased in a dose-dependent manner the cytotoxic activity of intact cytolytic T cells. However, cytotoxicity was not completely suppressed, and only in the case of CTL exhibiting low efficiency in killing their targets. It is proposed that lipoproteins inactivate perforin and may thereby inhibit a possible lysis of innocent bystander cells.
从细胞毒性T淋巴细胞（CTL）中分离出的细胞质颗粒能以非特异性方式裂解红细胞或肿瘤细胞系。高度纯化颗粒的活性在高达1/10,000的稀释度下会被人或兔血清抑制。人血清的主要抑制活性通过色谱法分离出来，确定为高密度脂蛋白（HDL）。HDL不仅在浓度为70 ng/ml时抑制分离颗粒的裂解活性，还抑制颗粒中存在的纯化的成孔蛋白穿孔素的活性。纯化的低密度脂蛋白同样具有活性。由于CTL颗粒活性在与脂蛋白磷脂含量相当的浓度下被纯卵磷脂囊泡抑制，脂蛋白的脂质部分可能是颗粒失活的原因。脂蛋白还以剂量依赖的方式降低完整细胞毒性T细胞的细胞毒性活性。然而，细胞毒性并未被完全抑制，且仅在CTL对其靶标杀伤效率较低的情况下如此。有人提出，脂蛋白使穿孔素失活，从而可能抑制无辜旁观者细胞的潜在裂解。
