Antibody response of Echinococcus granulosus infected mice: Protoscolex specific response during infection is associated with decreasing specific IgG1/IgG3 ratio as well as decreasing avidity

Abstract

The antibody response was followed during 68 weeks in 17 Balb/c mice intraperitoneally (i.p.) infected with Echinococcus granulosus protoscoleces (PSC) and in three mice i.p. immunized with dead PSC. Titres of antibodies recognizing peptidic and glucidic PSC epitopes, as well as their isotypic and avidity profiles were followed by ELISA. In addition, antigen recognition patterns were analysed by immunoblot. The response against carbohydrate epitopes was dominant in infected and immunized mice but stronger in the first group. Infected mice showed similar profiles of specific IgG and IgM with maximum titres from week 38 to 53. Although IgG1 and IgG3 were the predominant antibody subclasses, the ratio of IgG1/IgG3 antibody titres as well as antibody avidity decreased during the experiment, encompassing a decrease in recognition of peptidic epitopes. Immunized mice did not show significant levels of specific IgM and, after week 15, showed IgG titres lower than the infected mice. IgG1 was the predominant IgG subclass during all the experiment with background levels of IgG3. The mean Ab avidity was high and showed no significant changes during immunization. Different patterns of response were thus produced by dead and developing live parasites. Although high avidity IgG1 antibodies were early found in both cases, lower avidity IgG3 antibodies were increasingly produced afterwards only in infected animals. The isotype switch and avidity decrease observed only during infection are consistent with a possible parasitic mechanism to evade host immunity.

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

“…The authors concluded that MF inhibited the production of a multitude of cytokines, regardless of the cell In conclusion, our results suggest that Em492 antigen may be an important molecule in the survival strategies employed by E. multilocularis metacestodes. Furthermore our results are in line with other studies that show that glycosylated moieties from different parasitic preparations of E. multilocularis and of E. granulosus induce significant humoral immune responses in experimental infection models (9,16,39,48). The present study serves as an initial step for further investigations on the biological relevance of the Em492 antigen during E. multilocularis infection.…”

“…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…”

Major Carbohydrate Antigen ofEchinococcus multilocularisInduces an Immunoglobulin G Response Independent of αβ+CD4+T Cells

“…Furthermore, chronically infected mice maintained a markedly low-avidity IgG response to the LL antigen Em2(G11). A similar phenomenon had been observed in infections with the closely related parasite E. granulosus (43).…”

Assessment of the effect of Allium sativum on serum nitric oxide level and hepatic histopathology in experimental cystic echinococcosis in mice

“…In this model, the host reacts to the protoscoleces producing innate local and adaptive systemic responses (Severi et al 1997).…”