Singh A, Kang E S, Greenhaw J, Dorsett P
Department of Pediatrics, University of Tennessee, Memphis 38163.
J Immunol. 1989 Jul 1;143(1):203-7.
The possibility that circulating immune complexes (IC) could modify lipoprotein lipase (LPL) activity or release was explored in in vitro systems. IC were precipitated at antibody-Ag equivalence by using specific rabbit antisera and Ag from inactivated rubella virus and hemagglutinins from purified whole virions from three prototype strains of influenza (A/Brazil, A/Bangkok, and B/Singapore) as well as from a combined diphtheria and tetanus toxoid adsorbed with inactivated pertussis. After resolubilization, these IC were exposed to delipidated homogenates of rat epididymal fat pads before assay for LPL activity. LPL activity was stimulated two- to three-fold by the presence of 20 to 40 micrograms IC protein. This effect is not caused by the individual components of the IC because neither the specific Ag nor the individual antisera had any significant effect on LPL activity. With the rubella IC, a greater stimulatory effect was seen with increase in IC protein. With the influenza and diphtheria, pertussis, tetanus (DPT) IC, however, inhibition occurred when IC protein exceeded the amount of protein used for the LPL assay. C did not appear to be involved because IC prepared with heated antisera had similar effects. When intact rat epididymal fat pads were exposed to the rubella, influenza, or DPT IC, LPL activity recovered in the suspension medium was increased in each instance compared with pads exposed to a comparable amount of albumin. These findings may have implications for specific lipid changes that may occur during the immediate post-infectious period following rubella, influenza, or infections with the several bacteria whose Ag were present in the DPT IC used in these studies.
在体外系统中研究了循环免疫复合物（IC）能否改变脂蛋白脂肪酶（LPL）活性或释放的可能性。通过使用特异性兔抗血清以及来自灭活风疹病毒的抗原、三种甲型流感原型毒株（A/巴西、A/曼谷）和乙型流感原型毒株（B/新加坡）纯化全病毒体的血凝素，以及吸附有灭活百日咳杆菌的白喉和破伤风类毒素混合物，在抗体与抗原等当量时沉淀IC。重新溶解后，在测定LPL活性之前，将这些IC与大鼠附睾脂肪垫的脱脂匀浆一起孵育。20至40微克IC蛋白的存在可使LPL活性提高2至3倍。这种效应不是由IC的单个成分引起的，因为特异性抗原和单个抗血清对LPL活性均无显著影响。对于风疹IC，随着IC蛋白量的增加，刺激作用增强。然而，对于流感和白喉、百日咳、破伤风（DPT）IC，当IC蛋白超过用于LPL测定的蛋白量时，会出现抑制作用。补体似乎未参与其中，因为用加热抗体制备的IC具有相似的效应。当完整的大鼠附睾脂肪垫暴露于风疹、流感或DPT IC时，与暴露于等量白蛋白的脂肪垫相比，每种情况下悬浮培养基中恢复的LPL活性均增加。这些发现可能与风疹、流感或感染后急性期可能发生的特定脂质变化有关，这些感染是由本研究中DPT IC中存在的几种细菌的抗原引起的。
