Studies on the Seroimmunodiagnosis of Parasitic Diseases

기생충질환(寄生蟲疾患)의 면역혈청학적(免疫血淸學的) 진단(診斷)에 관한 연구(硏究)

In many of the helminthic infections, diagnosis is accomplished by the demonstration of the eggs or, occasionally the adult worms or their parts. Diagnosis can be made by the identification of larval stage obtained from stool or surgically extracted materials too. However some kinds of parasitic disease can not be diagnosed by above mentioned procedure alone. Brain cysticercosis, ectopic paragonimiasis, Capillaria hepatica infection in liver is a good example. In such a case, immunologic method would be helpful for the decision of physician. In this paper, immunologic tools such as indirect hemagglutination test, indirect fluorescent antibody test, circumoval precipitation test, ELISA, western blot were applied for the diagnosis of Clonorchis sinenisis, Cysticercosis and C. hepatica a infection and their efficacy was evaluated. The results obtained were as follows ; 1) In the diagnosis of clonorchiasis, ELISA revealed sensitiveity of 83.3%, but cross reaction against antibody of Paragonimus westermani and Taenia species were observed. For the identification of cross reaction and species specific band of Ag-Ab reaction, western blot was applied. 59Kd relative molecular weight and 21Kd band were identified as a Clonorchis sinensis specific band. OD values of ELISA performed with sera of 18 months after praziquantel treatment decreased to half level compared to that of before treatment. Negative conversion rate of ELISA after 18 months of treatment was 60%. 2) In the diagnosis of cysticercosis, IFAT disclosed 95.8%(23/24) of sensitivity and reaction was most strongly occurred in inner membrane. ELISA revealed 90.0% (36/40) of sensitivity, but cross reaction was observed in both technique. In western blot, 91, 63 and 21Kd Mw bands were identified as a strongly positive band. Among them 63Kd band showed positive reaction against almost all sera of cysticercosis patient. 3) Circumoval precipitation, ELISA, IFAT, showed 85.0% of sensitivity in the diagnosis of C. hepatica infection in rat. The antigenic localities were inner membrane of sectioned egg antigen on the prectipitates around the mucoid plugs which were induced by circumoval precipitation reaction. Sera from rats infected with 2000eggs were collected periodically to observe the changing patterns of antibody titers by IFAT and ELISA, which showed that high titers were detected at weeks 3 and 5, then gradually declined through weeks 9until to negatively converted at weeks 13.

우리나라에서 문제가 되고 있는 몇몇 기생충질환을 대상으로 각종의 혈청학적 진단법을 적용시켜 진단적 가치 및 의의에 대하여 검토하였다. 연구대상 기생충은 간흡충, 낭미충, Capillaria hepatica이었으며, 주로 간접 형광항체반응, ELISA, western blot등의 기법을 적용시켜 보았다. 결과를 요약하면 다음과 같다. 1) 간흡충증에 있어서 ELISA는 83.3%의 민감도를 나타낸 반면 폐흡층 및 조충과의 교차반응이 인정되었다. ELISA는 간접혈구응집반응, 간접형광항체 반응에 비해 우수한 성적을 보이고 있었다. 앞서 기술한 교차반응을 구별하고 항원-항체반응의 특이항원대를 알아보기 위해 실시한 western blot의 결과 59Kd band와 21K의 band는 간흡충감염자 혈청이외에는 반응하지 않아 종특이성이 있는 것으로 판단되었다. Praziquantel로 치료한 다음 18개월 후에 혈청 및 뇨를 이용하여 ELISA로 검사한 결과 OD치는 치료전의 약 1/2수준으로 감소하였고, 음전률은 60%에 이르렀다. 간접혈구응집반응을 이용할 경우 치료 18개월 후 80%가 음전되었다. 2) 낭미충증 진단에 있어서 간접형광항체반응은 95.8%(23/24) 민감도를 나타내었으며 내막에서 가장 강한 반응을 나타내었다. ELISA 역시 90.0%(36/40)의 높은 민감도를 나타내었으나 두 방법 모두에서 다른 기생충감염자 혈청과의 교차반응이 인정되었다. Western blot 에서 볼때 91, 63, 21Kd의 band가 종특이한 것으로 나타났으며, 이중 63Kd의 항원대가 일관성 있게 낭미충 감염 혈청과 반응하였다. 3) Capillaria hepatica 충란을 이용한 난주위침강반응 및 간접형광항체법에서 85.0%의 민감도를 나타내었으며, 초록색의 특이한 형광이 점막전주위 및 충란절단면의 내막에서 관찰되었다. 수용성충란항원을 이용한 ELISA에 있어서도 85.0%의 민감도를 나타내었다. 항체가 감염후 3~5주부터 급격히 상승하기 시작하여 9주부터 점차 감소되어 감염후 13주에는 음성으로 전환되었다.