Ramaprasad P, Harinath B C
Department of Biochemistry, Mahatma Gandhi Institute of Medical Sciences, Sevagram, India.
J Trop Med Hyg. 1995 Feb;98(1):35-40.
Fractionated urinary filarial antigen UFA C2 has shown high antigenic activity after absorption of urinary albumin present in the fraction. As little as 500 ag (10(-18) g) of albumin absorbed UFA C2, labelled as UFA C2-A, was found to be sufficient to detect filarial antibody. Stick enzyme immunoassay to assess the immunodiagnostic potential of UFA C2-A indicated filarial IgG antibody in 89% of microfilaraemic (mf) cases, 84% of clinical filariasis and 7% of endemic normals. UFA C2-A was found to be present in circulation in active as well as clinical infections as observed by inhibition assay using UFA C2-A penicillinase conjugate. Eighty-six per cent of mf, 50% of clinical cases and 6% of endemic normal subjects revealed parasite antigen to UFA C2-A on further serological analysis. None of the non-endemic normal sera showed the presence of filarial antibody/antigen to UFA C2-A. Furthermore, the test to determine phosphorylcholine (PC) bearing epitopes in UFA C2-A indicated no immunological reaction with anti-PC monoclonal antibody by avidin-biotin enzyme linked immunosorbent assay (ELISA). The highly sensitive and more easily obtainable non-PC urinary filarial antigen, UFA C2-A, is of great immunodiagnostic interest for lymphatic filariasis.
分级尿丝虫抗原UFA C2在去除该分级组分中存在的尿白蛋白后显示出高抗原活性。发现低至500 ag（10⁻¹⁸ g）经白蛋白吸收的UFA C2（标记为UFA C2-A）足以检测丝虫抗体。用于评估UFA C2-A免疫诊断潜力的棒式酶免疫测定表明，在89%的微丝蚴血症（mf）病例、84%的临床丝虫病病例和7%的地方性正常人群中存在丝虫IgG抗体。通过使用UFA C2-A青霉素酶缀合物的抑制试验观察到，UFA C2-A在活动性感染以及临床感染中均存在于循环中。进一步的血清学分析显示，86%的mf病例、50%的临床病例和6%的地方性正常受试者对UFA C2-A显示出寄生虫抗原。非地方性正常血清均未显示存在针对UFA C2-A的丝虫抗体/抗原。此外，通过抗生物素蛋白-生物素酶联免疫吸附测定（ELISA）确定UFA C2-A中含磷酰胆碱（PC）表位的试验表明，其与抗PC单克隆抗体无免疫反应。高度敏感且更容易获得的非PC尿丝虫抗原UFA C2-A对淋巴丝虫病具有重要的免疫诊断意义。
