Evasion of Trypanosoma cruzi from complement lysis

Area of Science:

• Immunology
• Biochemistry
• Parasitology

Background:

• The complement system (C) is a crucial part of innate immunity, involving complex protein interactions.
• C activation occurs via classical and alternative pathways, generating inflammatory peptides and the membrane attack complex.
• Trypanosoma cruzi, a parasite, possesses mechanisms to evade complement-mediated lysis.

Purpose of the Study:

• To review the complement system's properties and activation pathways.
• To identify and characterize Trypanosoma cruzi surface components involved in evading complement lysis.
• To investigate the mechanism of evasion, comparing it to known complement regulatory factors.

Main Methods:

• Review of complement system biochemistry and biology.
• Identification of Trypanosoma cruzi surface components.
• Enzymatic, chemical, and physical treatments to inactivate/remove surface components.
• Chromatographic isolation of components.
• Functional assays to assess interference with C3 convertase.

Main Results:

• Detailed description of complement system components, activation pathways (classical and alternative), and regulatory mechanisms.
• Identification of specific Trypanosoma cruzi surface components involved in evading complement lysis.
• Demonstration that these components can be inactivated by various treatments and isolated chromatographically.
• Evidence suggests these components inhibit C3 convertase formation or function, mimicking the decay accelerating factor (DAF).

Conclusions:

• Trypanosoma cruzi employs surface components to evade complement-mediated attack.
• These components interfere with complement activation similarly to host regulatory proteins like DAF.
• Understanding these evasion mechanisms is vital for developing therapeutic strategies against Chagas disease.