Dr. Murai Éva szerk.: Parasitologia Hungarica 11. (Budapest, 1978)

Agar gel methods Among the agar gel methods employed, double diffusion in gel (DDG), Immunoelectrophoresis (IEP), and countercurrent electrophoresis (CEP) are the three most popular. GUISANTES and YARZABEL (1971) evaluated the sensitivity of DDG, and found the technique to be more sensitive than IEP but had a higher rate of nonspecific results. CONTRERAS and KNIERIM (1974) obtained the opposite results. EOMBARDIERI et al. (1974), employing agarose in a barbital-glycine-buffered saline, tested 4 antigens and 58 sera in an Ouchterlony plate method. The sensitivity of the DDG was compared to that of the IHAT. The DDG test was reactive with 49 (85%) of the sera, whereas the IHA reacted with 41 (71%). In the Immunoelectrophoresis (IEP) test with 49 sera positive by DDG, 14 (28. 6%) did not show "Band 5." The antigens used were concentrated hydatid cyst fluid, a purified lipoprotein antigen A and B (ORIOL et al., 1971), isolated antigen B, and a polysaccharide antigen (RUSSI et al. , 1974). The most reactive antigen was antigen A. GUISANTES and VARELA-DIAZ (1975) evaluated 25 sera by DDG. They reported 100% sensitivity and specificity. GUISANTES and YARZABAL (1975) evaluated DDG against IEP and found ahigher sensitivity for the former (88.7%) against 82. 2% for the latter. The nonspecific response was 20.9%. Immunoelectrophoresis (IEP) is the test of choice for demonstrating the specific band 5 of E. granulosus infections. Since publication of the classic paper on diagnosis by IEP by CAPRON et al. (1967), the test has been evaluated in numerous studies (Table 5). Several points have emerged. Band 5 is not found in all sera from patients with E. granulosus infection. Band 5 may be a complex of bands (VARELA-DIAZ et al. , 1975c). The test has been carefully standardized (GUISANTES et al. , 1975). Because of the specificity of IEP, when band 5 can be identified, many workers recommend this method as the diagnostic method of choice. The recent literature on IEP is outlined in Table 5. Countercurrent electrophoresis (CEP), which has been called cross-over electrophoresis, counter Immunoelectrophoresis, electrosineresis, and immunoelectrodiffusion, is essentially diffusion in agar in an electrical field. This technique has all the advantages of DDG with the added advantage that the reaction can be completed in from 15 minutes to several hours, depending on the antigen used. Some workers find the method slightly more sensitive than IEP. One of the drawbacks of CEP is its inability to readily recognize Band 5. The technique can be performed on plates coated with agarose or with cellulose acetate membranes (GENTILINI and PINON, 1972). Using CEP, PINON (1976) claims he can detect from the characteristic "glove finger" pattern of the bands whether or not the cyst is ready to rupture. Another major advantage of CEP is that, compared to IEP, it requires less concentrated antigens. CEP has been used routinely in France (PINON, 1976), with excellent results. The recent literature is listed in Table 6. New immunologic methods A solid phase radioimmunoassay (RIA) for the diagnosis of hydatidosis was reported by MUSIANA et al. (1974). This technique employed 125t radioidinated human anti-EA binding reaction. The sensitivity of RIA is well recognized, but the technique requires purified antigen (which is available for hydatid disease) and rather expensive specialized equipment for handling labelled materials. The ELISA method, however, combines the principle of RIA and IFT and does not require specialized equipment. For this reason, the RIA procedure will probably not be widely used. A host lymphocyte transformation test with echinococcus antigens (EA) was reported by YUSUF et al. (1975). Lymphocytes from patients with hydatidosis showed statistically significant lymphocyte transformation with human and sheep hydatid fluid or scolex antigens when compared to lymphocytes from normal individuals. Patients with high results on lymphocyte transformation tests had low serologic titers by IHAT's. In vitro tests for the detection of cell mediated immunity (CMI) in parasitology have not been widely used. Blast transformation is just one of many techniques that may become part of the diagnostic armamentarium. A possible extension of the IFT may be the adaptation of the use of defined antigen substrate spheres (DASS) to the diagnosis of hydatid disease. This technique was initally developed for the diagnosis of schistosomiasis (DEELDER and PLOEM, 19 74) and is based on the