关键词: 日本血吸虫, 尿抗原检测, 尿CCA, 试剂条免疫试验

Abstract: AIM:To set up a simple immunoassay for detection of the excreted antigens in host urine.METHOD:A modified double anitbody sandwich ELISA in the form of a strip reagent which combined the advantages of both dot ELISA and plate ELISA for the detection of the gut associated circulating cathodic antigen(CCA) in the urine of Schistosoma japonicum infected rabbits and patients was developed.RESULTS:All the 9 reconstituted lyophilized urine samples collected from heavily infected rabbits,stored for over 10 years,gave strong positive reactions up to an end point titre of 512 -1 ,while only one out of 11 urine samples from normal rabbit stored and reconstituted in the same manner showed a weak reaction which faded at a dilution of 8 -1 .Urine CCA detections in 58 schistosomiasis patients collected from Sichuan Province,China and in 60 healthy students from the Shanghai Second Medical University revealed an assay sensitivity of 43.1% and a specificity of 96.7%. The detectability has been found similar to the parallelly performed plate ELISA for urine CCA.A certain degree of diagnostic complementarity in parallel up to 58.6% in these patient samples was seen with no increase of false positive cases.For identification of the diagnostic specificity,an appropriate amount of the capture antibody was added to the infected rabbit urine,a dose dependent competitive inhibition of the reaction intensity was observed,indicating the specific recognition of the target molecules in the urine by the anti CCA McAb system.The possible diagnostic complementarity via different methods using the same probe system was discussed.CONCLUSION:Results of this study have revealed the possibility as well as various advantages of the sandwich reagent strip assay to be used in the field for an non invasive detection of the excreted antigens in urine of infected individuals.