Holmberg M, Shenton F C, Franzén L, Janneh K, Snow R W, Pettersson U, Wigzell H, Greenwood B M
Department of Immunology, Karolinska Institute, Stockholm, Sweden.
Am J Trop Med Hyg. 1987 Sep;37(2):230-4. doi: 10.4269/ajtmh.1987.37.230.
A DNA probe consisting of 21 base pair repeats obtained from a Tanzanian isolate of Plasmodium falciparum, cloned in pBR322 and labeled with 32P by nick translation was used to detect malaria parasitemia in samples obtained during a malaria survey undertaken in The Gambia. In an initial trial the hybridization assay had a specificity for P. falciparum of 100% and a sensitivity of 68%. False negative results were obtained only on samples with low parasitemia. Assay of red cells collected during an earlier malaria survey which had been stored for 1 year at -20 degrees C gave a higher level of sensitivity (85%), suggesting a beneficial effect from freezing and thawing. This was confirmed by examining in the same assay red cells processed immediately after collection and after 2 weeks of storage at -20 degrees C. Freezing and thawing gave a 21% increase in positivity, and a sensitivity of 100% was achieved with the frozen samples. Quantitation of autoradiographs by visual inspection and by scintillation counting gave a reasonable correlation with parasite counts. The DNA hybridization assay has considerable promise as an epidemiological tool.
一种DNA探针，由从坦桑尼亚恶性疟原虫分离株获得的21个碱基对重复序列组成，克隆于pBR322并通过缺口平移用32P标记，用于检测在冈比亚进行的疟疾调查期间采集的样本中的疟疾寄生虫血症。在初步试验中，杂交试验对恶性疟原虫的特异性为100%，灵敏度为68%。仅在寄生虫血症水平低的样本上获得假阴性结果。对在早期疟疾调查期间采集并在-20℃下储存1年的红细胞进行检测，灵敏度更高（85%），表明冻融有有益效果。通过在同一试验中检测采集后立即处理的红细胞以及在-20℃下储存2周后的红细胞，证实了这一点。冻融使阳性率提高了21%，冷冻样本的灵敏度达到了100%。通过目视检查和闪烁计数对放射自显影片进行定量，与寄生虫计数有合理的相关性。DNA杂交试验作为一种流行病学工具具有很大的前景。
