Curtiss L K, DeHeer D H, Edgington T S
J Immunol. 1977 Feb;118(2):648-52.
An apparent subspecies of normal human serum low density lipoprotein (LDL-In) has been identified with suppressive activity for early or facilitating events of human lymphocyte mitogen and allogenic cells stimulation in vitro. This report describes the effects of in vivo administration of LDL-In on the mouse anti-SRBC immune response. Human LDL-In is not species specific and was capable of suppressing the in vivo mouse anti-sheep erythrocyte (SRBC) hemagglutination response by 88% after the administration of 500 to 600 mug LDL-In IV, whereas human serum high density lipoproteins and fibrinogen had no effect. Maximal suppression occurred only when LDL-In was injected 24 to 48 hr before antigen administration. Simultaneous or subsequent injection of LDL-In had no effect. The activity of LDL-In was influenced by antigen dose and maximal at low antigen doses. The number of splenic plaque-forming cells was also reduced indicating a suppression of the clonal expansion of primary B cells to antibody-secreting cells rather than only suppression of antibody synthesis by differentiated B cells and their progeny. These observations suggest the hypothesis that endogenous LDL-In could play an important immunoregulatory role in the maintenance of immune homeostasis and the "natural" suppression of non-productive lymphocyte proliferation.
已鉴定出一种正常人血清低密度脂蛋白（LDL-In）的明显亚类，其对体外人淋巴细胞有丝分裂原和同种异体细胞刺激的早期或促进事件具有抑制活性。本报告描述了体内给予LDL-In对小鼠抗SRBC免疫反应的影响。人LDL-In无物种特异性，静脉注射500至600μg LDL-In后，能够抑制体内小鼠抗绵羊红细胞（SRBC）血凝反应达88%，而人血清高密度脂蛋白和纤维蛋白原则无此作用。仅当在给予抗原前24至48小时注射LDL-In时才出现最大抑制作用。同时或随后注射LDL-In均无作用。LDL-In的活性受抗原剂量影响，在低抗原剂量时最大。脾斑块形成细胞数量也减少，表明主要是抑制了初级B细胞向抗体分泌细胞的克隆扩增，而不仅仅是抑制分化的B细胞及其后代的抗体合成。这些观察结果提示了一个假说，即内源性LDL-In可能在维持免疫稳态和对非生产性淋巴细胞增殖的“天然”抑制中发挥重要的免疫调节作用。
