Specific and non-specific parasite-induced changes in lymphocyte responses were analysed in C57/BL/6J mice after intrahepatic infection with Echinococcus multilocularis. Spleen cells harvested at selected times after infection were in vitro stimulated with mitogens or a crude soluble parasite extract (EmAg) at an optimized dose. Cell proliferative responses to Con-A were not modified by the infection over the first 22 weeks. In contrast, LPS-induced responses were decreased from the 13th week. A strong CD4+ proliferative T-cell response to the parasitic extract of infected mouse spleen cells was observed at the early stage of infection. This response then progressively decreased but remained significantly higher than that of control mice until the 19th week of infection. Cytokine production was investigated after in vitro EmAg stimulation of spleen cells. IFN-gamma, IL-2, IL-5 were produced within the first weeks after infection whereas the detection of IL-10 was slightly delayed. Thus, the promotion of the disease does not appear associated with the expansion of one rather than another T-cell subset in C57BL/6J mice. A general immunosuppression affecting both mitogenic and parasite-specific T-cell responses was observed at the end of the infection.

In A. fumigatus, the prevalence of azole resistance is currently low in the haematological population in the Paris area. Surveillance programmes for azole resistance to adapt antifungal treatments are warranted for clinical isolates of A. fumigatus.

The Echinococcus Western Blot IgG (LDBIO Diagnostics, Lyon, France), using a whole larval antigen from Echinococcus multilocularis, was evaluated for serodiagnosis and differentiation between two human parasitic infections of worldwide importance: cystic echinococcosis, due to Echinococcus granulosus, and alveolar echinococcosis, due to E. multilocularis. Fifty and 61 serum samples from patients with cystic and alveolar echinococcosis, respectively, were used for assessing diagnostic sensitivity. The sensitivity of the assay was compared with those of screening tests used for these applications. Sera used for assessing cross-reactivities were from 154 patients with other diseases, either parasitic or not. The assay allowed the detection of serum immunoglobulin G antibodies in 97% ofEchinococcus-infected patients. It had a higher sensitivity than screening assays for the detection for each echinococcosis. The assay allowed us to correctly distinguish between E. granulosus- and E. multilocularis-infected patients in 76% of cases. It did not allow us to distinguish active from inactive forms of both echinococcoses. The occurrence of cross-reactivities with neurocysticercosis indicates the necessity for retesting sera with species-specific antigens, for rare patients with neurologic disorders. This study shows the usefulness of the commercially available Echinococcus Western Blot IgG for the serological confirmation of human echinococcosis.

Using an experimental model of hepatic Echinococcus multilocularis infection in C57BL/6J mice, intraperitoneal administration of 0.8 microgram of recombinant IL-12 to mice with an established infection was shown to reduce the parasite burden as soon as two weeks after the end of treatment. At that time, in vitro Echinococcus multilocularis-induced spleen T cell proliferative responses as well as IFN-gamma and IL-5 production were higher in IL-12 treated mice than in untreated mice. Administration of 0.8 microgram of IL-12 at the time of infection was shown to be without effect on the parasite establishment. However, this treatment greatly inhibited the subsequent metacestode development. Indeed, ten weeks after infection, it induced a complete healing in 37.5% of mice. At that time, the development of metastases was inhibited in 68.75% of IL-12-treated mice. This reduction of parasite burden was mainly associated with a strong proliferation of spleen cells to E. multilocularis antigen and with a high IFN-gamma production. Altogether, our results show that IL-12 is of crucial importance in inhibiting the larval growth after the metacestode establishment in the liver and suggest that this cytokine could be of potential value in the treatment of human alveolar echinococcosis.

To analyze collagen and other matrix protein deposits in experimental alveolar echinococcosis as well as the expression of lysyl oxidase, the enzyme that initiates the first steps in the pyridinoline cross-linking of collagen, and to establish a relationship between resistance/susceptibility to Echinococcus multilocularis larval growth and fibrogenesis, we compared AKR/J mice (susceptible to E. multilocularis infection) with NMRI mice (resistant hosts) in this study. Collagen deposits in the lesions were evaluated using a colorimetric method; the nature of matrix proteins involved in the periparasitic fibrosis and lysyl oxidase expression were assessed using immunostaining on tissue sections. The results obtained in this sequential study confirm that fibrogenesis is an important aspect of the host immune reaction against parasitic development and that both the extent and the course of matrix protein deposition differ in the liver of susceptible and resistant mice, respectively. The long-lasting expression of alpha-actin and lysyl oxidase by host cells in NMRI mice suggests that in this resistant strain, fibrosis was not only more developed but also more highly cross-linked and, thus, less sensitive to collagenases than in susceptible mice. A very strong expression of lysyl oxidase by parasitic cells was observed in both strains of mice; the observation that E. multilocularis itself has a role in lysyl oxidase cross-linking of host collagens can be hypothesized and would be a new example of parasite-host interplay.

Alveolar echinococcosis (AE) is the most potentially lethal parasitic zoonosis of the nontropical areas in the northern hemisphere, where cystic echinococcosis (CE) is also endemic. Both AE and CE are highly endemic in China, and both serologic detection of echinococcosis, either AE or CE, and differentiation of AE from CE are crucial problems. Evaluation of Western blot analysis (WB) and enzyme-linked immunosorbent assay (ELISA) for the Em18 antigen, using affinity-purified and recombinant Em18, was carried out "blindly" using 60 human sera from patients diagnosed in France. The results were compared with those obtained using a commercially available Echinococcus WB immunoglobulin G (IgG) kit developed in France. The Em18 WB and Echinococcus WB IgG showed very similar results for detection of AE. Both affinity-purified Em18 or a recombinant Em18 WB and Echinococcus WB IgG seem useful for identification of AE, and the latter seems appropriate for both AE and CE, whereas affinity-purified Em18 ELISA and the newly developed recombinant Em18 ELISA appear to be suitable for detection of AE, especially for epidemiological surveys.Alveolar echinococcosis (AE), caused by the metacestode of the fox tapeworm, Echinococcus multilocularis, is the most potentially lethal parasitic zoonosis of the nontropical areas in the northern hemisphere, where cystic echinococcosis (CE), caused by the metacestodes of the dog tapeworm, E. granulosus, is also endemic. For example, both AE and CE are highly endemic in China (8,19) and serological detection of echinococcosis, either AE or CE, and differentiation of AE from CE are crucial problems, since the pathogenicity of these two types of echinococcosis and the treatment of patients with these diseases are critically different (14,16).In Japan and France, immunoblotting (Western blotting [WB]) assay systems have been developed for differentiation of AE from other diseases (4-7). The Asahikawa Medical College (AMC) group in Japan has focused on the detection of antibody response to the Em18 antigen (approximately 18 kDa) extracted from protoscoleces of E. multilocularis (4, 9, 15) and has tried to purify Em18, which shows a single band in WB, and to make it available for enzyme-linked immunosorbent assay (ELISA), using preparative isoelectric focusing (PIEF). Since purification of Em18 by PIEF takes longer and the yield is not as great, we have shifted to purification of Em18 by affinity chromatography (AffEm18) and production of a recombinant Em18 (RecEm18) for WB and ELISA (7, 9, 10, 13, 18). Echinococcus WB immunoglobulin G (IgG) (EchWB IgG; LDBIO Diagnostics, Lyon, France), which has a high sensitivity for the detection of both AE and CE, is basically very similar to the AMC system since it also focuses on differentiation of AE and CE based on different banding patterns including antigen B (most predominant at 8 and 26 to 28 kDa), Em16, and Em18 in crude antigens. The merit of the latter system is that it detects both AE and CE on a single strip based on the difference in the banding...

SUMMARYCellular immiine responses have been shown lo be associated with ditferenlial evolutions of E. multilocularis infection in intermediale hosls. A relationship between course of delayed-type hypersensiiivity (DTH) against parasitic antigens and receptivity of murinc strains has been demonstrated recently. The aim of this study was to correlate resistance and sensitivity to E. multitocutaris infection with the phenotypic patterns of cells within the periparasitic granuloma. Evolution of the ratios. macrophages/T lymphocyte and Lyl/Ly2 T lymphocytes, was associated with the receptivity of the strains. Persistence of numerous L3T4-I-T lymphocytes and low numbers of macrophages and Ly2 + T lymphocytes were observed in the "resistant' C57BL.10 mice.Comparison of the results wilh course of the DTH against E. muttilocutaris anUgcns showed that the particular phenotypic pattern observed in resistant mice was associated with a particular profile of DTH after infection. These results and similar observations in human alveolar echinococcosis suggest that cell composition of the periparasilic granuloma might be of crucial importance in controlling the spontaneous development of E. multitocutaris larvae In (he intermediate host.

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