Diffley P
Infect Immun. 1978 Aug;21(2):605-12. doi: 10.1128/iai.21.2.605-612.1978.
The presence, location, host specificity, identity, and quantity of rat plasma proteins bound to bloodstream forms of Trypanosoma brucei subsp. brucei, T. brucei subsp. rhodesiense, and T. brucei subsp. gambiense were determined by a quantitative indirect fluorescent-antibody method and gel immunoassays. Fluorescence differences between trypanosomes obtained from rats and mice and treated with antiserum to normal rat plasma indicated that most, if not all, of the bound plasma proteins were host specific. Removal of plasma proteins by trypsinization of parasites provided evidence for their attachment to the surface of the parasite. The accreted proteins were found to be host albumin, immunoglobulin G (IgG), and complement (C3). The same quantities of these three plasma proteins were present on T. brucei subspecies collected from normal rats at 2 days postinfection, during low or peak parasitemias, or from cortisone-treated rats. IgM could only be detected on parasites collected from normal rats at peak parasitemia. With the aid of rocket immunoelectrophoresis, host albumin and IgG were found to account for 0.2 and 0.05%, respectively, of the total soluble proteins of the bloodstream forms. It was concluded from this study that: (i) host plasma proteins were bound to parasites early in the infection, suggesting a mechanism of adaptation to the mammalian host; (ii) the surface-bound IgG was not the result of a specific immune response against the parasites but might be the cause of C3 attachment; (iii) among the bloodstream forms of the three T. brucei subspecies, there were no differences in amounts of surface-bound albumin, IgG, or C3. A comparison between the present data dealing with T. brucei subspecies, on the one hand, and the previously published results concerning T. congolense, on the other, revealed significant differences in the amounts of the host plasma proteins attached to these hemoflagellates.
采用定量间接荧光抗体法和凝胶免疫分析法，测定了与布氏锥虫亚种、罗德西亚锥虫亚种和冈比亚锥虫亚种血流形式结合的大鼠血浆蛋白的存在情况、位置、宿主特异性、种类及数量。用抗正常大鼠血浆的抗血清处理从大鼠和小鼠体内获取的锥虫后，荧光差异表明，即使不是全部，大多数结合的血浆蛋白也具有宿主特异性。通过胰蛋白酶消化寄生虫去除血浆蛋白，为这些蛋白附着在寄生虫表面提供了证据。发现吸附的蛋白为宿主白蛋白、免疫球蛋白G（IgG）和补体（C3）。在感染后2天从正常大鼠体内收集的布氏锥虫亚种上，在低虫血症或高虫血症期间，或从经可的松处理的大鼠体内收集的布氏锥虫亚种上，均存在相同数量的这三种血浆蛋白。仅在高虫血症时从正常大鼠体内收集的寄生虫上检测到IgM。借助火箭免疫电泳法，发现宿主白蛋白和IgG分别占血流形式总可溶性蛋白的0.2%和0.05%。从这项研究得出的结论是：（i）宿主血浆蛋白在感染早期就与寄生虫结合，提示了一种适应哺乳动物宿主的机制；（ii）表面结合的IgG不是针对寄生虫的特异性免疫反应的结果，而可能是C3附着的原因；（iii）在三种布氏锥虫亚种的血流形式中，表面结合的白蛋白、IgG或C3的量没有差异。一方面，将处理布氏锥虫亚种的当前数据与另一方面先前发表的关于刚果锥虫的结果进行比较，发现附着在这些血鞭毛虫上的宿主血浆蛋白量存在显著差异。
