THE RATE OF PROLIFERATION AMONG AFRICAN TRYPANOSOMES IS A STABLE TRAIT THAT IS DIRECTLY RELATED TO VIRULENCE
THE RATE OF PROLIFERATION AMONG AFRICAN TRYPANOSOMES IS A STABLE TRAIT THAT IS DIRECTLY RELATED TO VIRULENCE
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DOI：
10.4269/ajtmh.1987.36.533
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发表时间：
1987-05-01
影响因子：
3.3
通讯作者：
TSEN, TNR
中科院分区：
文献类型：
--
作者：
DIFFLEY, P;SCOTT, JO;TSEN, TNR
本文研究了冈比亚布氏锥虫的生长速度与其毒力的关系。一个克隆的、单态的、生长缓慢的、相对无毒的T. B.以3- 5天的间隔通过免疫抑制小鼠连续传代冈比亚酵母。在感染的前2个开放日内测量的生长速率在前25代中没有显著变化，但到第50代时从11.9 ± 1显著降低。1.1 hr至9.0 ±。0.7来自第50代的克隆和三种不同的第二峰异源变体都具有统计学上相似的生长速率，表明增殖速率是稳定的性状。随着增殖速度的加快，毒力也相应增加。在寄生虫血症的第一个峰值（LD 50）中杀死50%正常远系交配小鼠所需的接种物从3 × 104显著下降。106个第一代寄生虫至4 ×105代50只寄生虫。快速和缓慢生长的生物体的致死负荷是相同的（> 2 × 104）。109锥虫/ml血液）。为了进一步将毒力与生长速率联系起来，对10个近缘株系的世代数进行了相关分析（r = 0.89）。B. gambiense和2行多形性T. B.将罗德西亚菌与其LD 50值进行比较。虽然锥虫增殖的速率在接种日至第二个开放日之间是相似的，但是一旦寄生虫血症超过3倍，其减慢至该水平的64%。108个微生物/ml宿主血液。这种生长抑制发生在类似程度的单形和多形性线的锥虫，在大约相同的寄生虫血症水平，在免疫抑制或免疫完整的小鼠。毒力不能相关的寄生虫血症的第一个高峰，一个多形性的锥虫系，或其变体抗原类型的后期测量的生长速度。
The relationship between the growth rate of Trypanosoma brucei gambiense and its virulence was investigated. A cloned, monomorphic, slow growing, and relatively avirulent line of T. b. gambiense was serially passaged at 3- to 5-day intervals through immunosuppressed mice. The growth rate measured within the first 2 patent days of infection did not vary significantly through the first 25 passages but by passage 50 had decreased significantly from 11.9 .+-. 1.1 hr to 9.0 .+-. 0.7 hr. A clone from passage 50 and three different second peak heterologous variants all had statistically similar growth rates, indicating that the rate of proliferation was a stable trait. With the faster rate of proliferation there was a corresponding increase in virulence. The inoculum necessary to kill 50% of normal outbred mice in the first peak of parasitemia (LD50) dropped significantly from 3 .times. 106 first passage parasites to 4 .times. 105 passage 50 parasites. The lethal load for both fast and slow growing organisms was the same (> 2 .times. 109 trypanosomes/ml of blood). To further link virulence and growth rate, a strong correlation (r = 0.89) was measured when generation times of 10 closely related lines of T. b. gambiense, and 2 lines of pleomorphic T. b. rhodesiense were compared to their LD50 values. While the rate of trypanosomal proliferation was similar between the day of inoculation through the second patent day, it slowed to 64% of that level once parasitemias exceeded 3 .times. 108 organisms/ml of host blood. This inhibition of growth occurred to similar degrees in both monomorphic and pleomorphic lines of trypanosomes, at about the same level of parasitemia, in both immunosuppressed or immunologically intact mice. Virulence could not be correlated to the growth rate measured late in the first peak of parasitemia, a pleomorphism of the trypanosomal line, or its variant antigen type.