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

Abstract

was predominantly of the IgG3 and IgG2a isotypes and of the IgG3 and IgG2b isotypes in CD40؊/؊ mice. This finding suggested that in vivo, the IgG response to major carbohydrate antigen Em2(G11) of E. multilocularis could take place independently of ␣␤ ؉ CD4 ؉ T cells and in the absence of CD40-CD40 ligand interactions; thus, the Em2(G11) antigen of the acellular LL represents a T-cellindependent antigen. Functionally, the encapsulating LL, and especially its major carbohydrate antigen, Em2(G11), seems to be one of the key factors in the parasite's survival strategy and acts by modulating the host immune response by virtue of its T-cell-independent nature.

Recent Advances in the Immunology and Serological Diagnosis of Echinococcosis

“…A large number of CD4(+) T lymphocytes are present in AE patients with aborted or dead lesions, whereas patients with active parasites display a significant increase in activation of predominantly CD8(+) T cells (Manfras et al, 2002) indicating that CD4(+) T cells may play a role in the killing mechanism. This is supported by experiments undertaken with genetically modified mice (Dai et al, 2001). Conversely, E. multilocularis is able to survive and persist in its host indefinitely for long periods of time.…”

Mechanisms of Immunity in Hydatid Disease: Implications for Vaccine Development

“…A large number of CD4 ϩ T lymphocytes are present in AE patients with aborted or dead lesions, whereas patients with active parasites display a significant increase in activation of predominantly CD8 ϩ T cells (37), indicating that CD4 ϩ T cells may play a role in the killing mechanism. This is supported by experiments undertaken with genetically modified mice (38). Conversely, E. multilocularis is able to survive and persist in its host indefinitely for long periods of time.…”

“…The physical barrier between E. granulosus and E. multilocularis cysts and their hosts is the parasite-derived laminated layer (LL), characterized by its rich high molecular weight polysaccharide composition. In E. multilocularis the LL and especially its major carbohydrate Ag Em2(G11), appear as key to the parasite's survival, acting by modulating the host immune response by virtue of its T cell-independent nature (38). Em2(G11), another carbohydrate component of the LL (Em492), as well as other parasite metabolites, also interfere with Ag presentation and cell activation, leading to a mixed Th1/Th2-type response during late infection (63).…”

Triggering and modulation of the host-parasite interplay byEchinococcus multilocularis: a review

“…the IgG response to the Em2(G11)-antigen takes place independently of alpha-beta+CD4+ T cells, and in the absence of interactions between CD40 and CD40 ligand (Dai et al 2001). Such parasite molecules also interfere with antigen presentation and cell activation, leading to a mixed Th1/Th2-type response at the later stage of infection.…”