Patil Shripad A, Katyayani S, Arvind N
National Institute of Mental Health and Neurosciences, Neuromicrobiology, NIMHANS, Bangalore, India.
J Immunoassay Immunochem. 2012;33(2):140-8. doi: 10.1080/15321819.2011.606862.
Cryptococcus neoformans is the causative agent of Cryptococcosis, a chronic and life-threatening infection common in AIDS patients. Sonicated proteins of cryptococci were reported to contain antigenic properties. In the present study antigens are prepared from cryptococcal culture filtrate and by sonication. Secretory antigens are prepared by precipitation of culture filtrate using saturated ammonium sulfate followed by dialysis. Prepared antigens are tested for the presence of antibodies in the CSF samples of cryptococcal meningitis cases by ELISA. Comparison is made between India ink staining, latex antigen test, and the antibodies to the sonicated and secretory antigens. The results indicate that although antigen could be detected in the majority of samples, antibody could also be detected to the extent of 80-85%. It is interesting to note that some samples that were negative for India ink staining also showed high antibody responses. Hence, antibody detection could be a valuable marker in association with India ink staining for the early diagnosis of the cryptococcal infection. This test may also counter false positivity encountered in latex antigen test. Antibody detection assay would be a viable alternative, which has 83% sensitivity and 100% specificity. Thus the presently described test aids in immunodiagnosis of cryptococcal infection.
新型隐球菌是隐球菌病的病原体，隐球菌病是一种在艾滋病患者中常见的慢性且危及生命的感染。据报道，经超声处理的隐球菌蛋白具有抗原特性。在本研究中，抗原由隐球菌培养滤液并通过超声处理制备。分泌性抗原通过用饱和硫酸铵沉淀培养滤液然后透析来制备。通过酶联免疫吸附测定（ELISA）检测制备的抗原在隐球菌性脑膜炎病例的脑脊液样本中抗体的存在情况。对墨汁负染色、乳胶抗原试验以及对经超声处理和分泌性抗原的抗体进行比较。结果表明，虽然大多数样本中可检测到抗原，但抗体的检测率也可达80 - 85%。值得注意的是，一些墨汁负染色阴性的样本也显示出高抗体反应。因此，抗体检测可能是与墨汁负染色相关的用于隐球菌感染早期诊断的有价值标志物。该检测还可对抗乳胶抗原试验中遇到的假阳性。抗体检测试验将是一种可行的替代方法，其灵敏度为83%，特异性为100%。因此，目前所描述的检测有助于隐球菌感染的免疫诊断。
