Modulation of the cellular immune response by a carbohydrate rich fraction from Echinococcus granulosus protoscoleces in infected or immunized Balb/c mice

Abstract

Infection of Balb/c mice with Echinococcus granulosus protoscoleces constitutes the model for secondary hydatid infection. The immune response of Balb/c mice infected with E. granulosus is characterized by secretion of antibodies specific for carbohydrate epitopes and production of type-2 cytokines. A role for glycoconjugates in the induction of type-2 responses has been suggested in other host--parasite systems. Although glycoconjugates are immunogenic in E. granulosus infection, the role of these molecules in the establishment of the type-2 response has never been analysed. In this study, a carbohydrate rich fraction (E4+) from E. granulosus protoscoleces was obtained using the monoclonal antibody E492/G1 specific for the moiety Galalpha(1,4)Gal which is widely represented in protoscoleces and other E. granulosus antigenic preparations. The results showed that E4+ was immunogenic in Balb/c mice evoking an antibody response mainly directed against carbohydrate epitopes. In addition, splenocytes from E4+-immunized mice showed suppressed proliferative responses to Con A and E4+ induced IL-10 secretion by E4+-primed and naive splenocytes. The fraction E4+ also was immunogenic in infected mice during early infection. In this case also, splenocytes from infected mice as well as peritoneal cells from infected or naive mice, when stimulated in vitro with E4+, secreted IL-10. Collectively, these results suggest that E4+ may be involved in immunosuppression phenomena and, by stimulating IL-10 secretion, may contribute to the induction and sustaining of the type-2 cytokine response established in early experimental infection.

Neutralizing Anti-IL-10 Antibody Blocks the Protective Effect of Tapeworm Infection in a Murine Model of Chemically Induced Colitis

“…Using DNBS to evoke what is considered a Th1-driven colitis (24), the present study shows that H. diminuta infection in a prophylactic regimen almost abolished the colitis, as assessed by clinical parameters, histological assessment, and biochemical markers (i.e., MPO). One interpretation of the data is that H. diminuta ameliorates colitis via the release of a particular factor, and indeed, like other parasitic helminths (25), H. diminuta Ag can block mitogen-driven T cell responses in vitro (26). However, in the nonpermissive murine system, the helminth never establishes or attains a significant biomass (15).…”

Characterization of a Secretory Annexin in Echinococcus granulosus

“…Mouse anti-PSC sera was obtained as previously described. 24 Every mouse was injected with 2,000 PSCs, and serum samples were collected after 9 months for subsequent western blot analysis. Polyclonal antibody against Eg-ANX was produced after a previous study.…”

Isolation and Characterization of a Secretory Component ofEchinococcus multilocularisMetacestodes Potentially Involved in Modulating the Host-Parasite Interface

“…The coupling of MAb E492/G1 to CNBr-activated Sepharose (Amersham Pharmacia Biotech, Düben-dorf, Switzerland) was done as described by Dematteis et al (11). Bound parasite molecules were eluted with 0.1 M glycine-HCl, pH 2.8.…”

“…In some experiments, coated wells were treated with either 50 mM NaIO 4 in 40 mM sodium acetate buffer (pH 5.5) for 1 h at 37°C or 50 g of proteinase K/ml for 1 h at 37°C to disrupt carbohydrate and protein epitopes, respectively. Following the blocking of unspecific binding sites (1% BSA in PBS, 1 h), plates were incubated with biotinylated MAb E492/G1 diluted 1:1,000 in PBS-0.05% Tween 20-0.05% BSA for 1 h at 37°C as described by Dematteis et al (11). After being washed, wells were incubated with streptavidin-alkaline phosphatase conjugate (PharMingen, San Diego Calif.) diluted 1:500 in PBS-0.3% Tween 20-0.05% BSA.…”

“…A. Wilson, J. Jaeken, and R. A. Dwek, Letter, Glycobiology 11:10, 2001). Several biological activities of pathogen carbohydrates have been described, such as antigenic activity (23,39,48,50), inhibition of cellular proliferation (32,44,53,54), mimicry of host components (37,55), and other immunosuppressive and immunomodulatory effects (9,11,40,56). Dematteis et al (11) have isolated a carbohydrate-rich fraction named E4…”