Abstract:

Objective To observe and compare the inspection effects of antigen substrate slides of Plasmodium cynomolgi （P. c）and Plasmodium falciparum（P. f）on the malaria antibody titer under different storage temperatures and time. Methods The densities of Plasmodium of P. c and P. f antigen slides were counted through a microscope，and the average numbers of Plas? modium in each field of vision were calculated. The pooled serum of patients with tertian malaria and falciparum malaria were treat? ed as antibody serum，and the dilutions were from 1∶5 to 1∶1 280. The two kinds of antibody slides were placed under the temper? ature of 4-6，25-27，33-35 ℃，and two slides of each kind were selected at Day 3，5，7，10 post?storage to detect the end point antibody titer of malaria by the indirect fluorescent antibody test. Meanwhile，the P. c and P. f antigen slides storing under -20 ℃ for 1 year and 2 years were placed under the aforementioned 3 temperature conditions for 3 d，and the changes of the antibody ti? ters were compared. Results The densities of Plasmodium in blood cells of P. c and P. f antigen slides were 2.00×105 /μl and 1.89×105 /μl，respectively，and the average numbers of Plasmodium in each field of vision were 157±13 and 142±9，respectively. The end point titers of antibody of P. c and P. f antigen slides placed under the temperatures of 4-6，25-27，33-35 ℃ were all on a downward trend after storing for 5 d. The average antibody titers of the two kinds of slides under temperature of 4-6 ℃ and above were 1∶440 and 1∶80，respectively，and there was a significantly statistic difference between them（t = 1.940， P＜0.05） . When P. c and P. f antigen slides storing under -20 ℃ for 1 year were placed under 4-6 ℃ for 3 d，the end point antibody titers were both 1∶640，while for those storing under -20 ℃ for 2 years，the end point antibody titers were 1∶320 and 1∶160，respectively， both the differences were statistically significant（tP. c=11.362，PP. c＜0.01； tP. f =38.845，PP. f＜0.001） . Conclusion The end point antibody titers for malaria detection of P. c and P. f antigen slides decrease gradually with the raise of temperature and the prolonging of time for storage.

Key words: Plasmodium cynomolgi； Plasmodium falciparum； Indirect fluorescent antibody test；Antigen； Antibody； Titer

摘要：

目的 观察比较食蟹猴疟原虫 （Plasmodium cynomolgi， P. c） 抗原片和人工培养恶性疟原虫 （Plasmodium falci? parum，P. f） 抗原片在不同保存温度与时间下检测疟疾抗体滴度的效果。方法 显微镜下计数2种抗原片原虫密度， 计算每个视野的平均原虫数。以间日疟和恶性疟病人的混合血清作为已知疟疾抗体血清， 稀释浓度为1∶5~1∶1 280。将2种抗原片置于4～6、 25～27、 33～35 ℃ 3组温度下， 于放置第3、 5、 7、 10天各取出2张， 用间接荧光抗体试验 （IFAT） 法检测抗体终点滴度， 并比较-20 ℃下贮藏1年和2年的2种抗原片， 在３个温度组保存3 d时抗体滴度的变化。结果 2种抗原片红细胞疟原虫密度分别为2.00×105 /μl和1.89×105 /μl， 每个视野平均疟原虫数分别为157±13和142±9。3个温度组P. c和P. f 抗原其抗体终点滴度均在5 d后呈下降趋势。2种抗原片在4～6 ℃组及以上组的平均抗体滴度分别为1∶440和1∶80， 差异有统计学意义 （t = 1.940， P＜0.05）。在4～6 ℃放置3 d， -20 ℃贮藏1年的P. c和P. f抗原片检测疟疾抗体的终点滴度均为1∶640； 贮藏2年的2种抗原片终点滴度分别为1∶320与1∶160， 差异均有统计学意义 （tP. c=11.362，PP. c＜0.01； tP. f = 38.845，PP. f＜0.001）。结论 P. c和P. f抗原片检测疟疾抗体终点滴度随存放温度的上升和时间的延长逐渐下降。

关键词: 食蟹猴疟原虫； 恶性疟原虫； 间接荧光抗体试验； 抗原； 抗体； 滴度