Cytokines from parasites: manipulating host responses by molecular mimicry

Area of Science:

• Parasitology
• Immunology
• Molecular Biology

Background:

• Helminth parasites employ sophisticated immune evasion strategies.
• These strategies often involve manipulating host cytokine networks.
• Transforming growth factor-β (TGF-β) signaling is a key target for parasite manipulation.

Purpose of the Study:

• To investigate the structure and function of TGF-β mimics (TGMs) secreted by Heligmosomoides polygyrus.
• To understand how TGMs interact with host TGF-β receptors and co-receptors.
• To elucidate the immunomodulatory roles of different TGM family members.

Main Methods:

• Analysis of TGM protein structure and domain functions.
• In vitro studies on TGM-induced T regulatory cell differentiation.
• In vivo assessment of TGM effects on allergic and intestinal inflammation models.

Main Results:

• Identified a family of ten TGMs secreted by H. polygyrus.
• TGM1 mimics TGF-β, induces Foxp3+ T regulatory cells, and reduces inflammation.
• Different TGMs exhibit varied domain structures, enabling distinct agonistic or antagonistic functions on specific cell types via co-receptor binding (e.g., CD44).

Conclusions:

• TGMs are highly evolved helminth immunomodulators that mimic host cytokines to bind TGF-β receptors.
• Specific TGM variants can act as agonists or antagonists, targeting different cell types.
• Helminth evasion molecules demonstrate diverse strategies for establishing and maintaining long-term infections.