Echinococcus multilocularis metacestode extract triggers human basophils to release interleukin-4

Area of Science:

• Immunology
• Parasitology
• Molecular Biology

Background:

• Parasitic helminth infections are linked to T helper 2 (Th2) immune responses and immunoglobulin E (IgE) production.
• The precise mechanisms driving these responses remain incompletely elucidated.
• A protein, IL-4-inducing principle from Schistosoma mansoni eggs (IPSE), was previously identified that stimulates IL-4 release from human basophils.

Purpose of the Study:

• To investigate whether helminth species share IL-4-inducing activities.
• To examine the effects of Echinococcus multilocularis extracts on human basophil immune responses.
• To determine the role of IgE in the mechanism of IL-4 induction by helminth extracts.

Main Methods:

• Preparation of extracts from metacestodes of Echinococcus multilocularis.
• Incubation of human basophils with E. multilocularis extracts.
• Measurement of basophil degranulation, histamine secretion, and cytokine release (IL-4, IL-13).
• IgE stripping and resensitization experiments on basophils.

Main Results:

• Echinococcus multilocularis extracts induced dose-dependent basophil degranulation and secretion of histamine, IL-4, and IL-13.
• The induction of IL-4 release was dependent on the presence of IgE on the basophil surface.
• These findings are analogous to previously observed properties of IPSE from Schistosoma mansoni.

Conclusions:

• Echinococcus multilocularis, like Schistosoma mansoni, can induce a Th2 immune response through the release of IL-4 from basophils.
• This suggests a conserved mechanism among different helminth species for initiating host Th2 immunity.
• The findings highlight the critical role of IgE in mediating helminth-induced Th2 responses via basophil activation.