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Glyceraldehyde-3-phosphate dehydrogenase of the parasitic nematode Haemonchus contortus binds to complement C3 and

S Sahoo1, S Murugavel, I K Devi

  • 1Division of Biochemistry, Indian Veterinary Research Institute, Izatnagar, UP, India.

Parasite Immunology
|August 10, 2013
PubMed

Insights

Researchers identified a complement-binding protein (H.c-C3BP) from the parasite Haemonchus contortus. This glyceraldehyde-3-phosphate dehydrogenase (GAPDH) protein inhibits host immune responses, offering potential for new parasite control strategies.

Area of Science:

  • Parasitology
  • Immunology
  • Biochemistry

Background:

  • Haemonchus contortus is a major gastrointestinal parasite affecting livestock like sheep and goats.
  • Parasite survival hinges on evading the host's immune system.
  • Understanding parasite immune evasion mechanisms is crucial for developing effective treatments.

Purpose of the Study:

  • To identify and characterize a novel complement-binding protein from Haemonchus contortus.
  • To investigate the role of this protein in modulating the host immune response.
  • To explore the potential of this protein as a therapeutic target.

Main Methods:

  • Biochemical isolation using C3-Sepharose chromatography.
  • Mass spectrometry for protein identification.
  • Molecular biology techniques including recombinant protein expression in E. coli.
  • Functional assays: hemolytic assay and Membrane Attack Complex (MAC) formation inhibition.
  • Immunological assays using antisera and infected animal sera.

Main Results:

  • A complement-C3-binding protein (H.c-C3BP) was identified from H. contortus excretory-secretory products.
  • Sequence analysis confirmed H.c-C3BP as glyceraldehyde-3-phosphate dehydrogenase (GAPDH).
  • H. contortus GAPDH demonstrated the ability to bind complement C3 and inhibit complement-mediated lysis and MAC formation.
  • The identified protein is secreted by the parasite and recognized by sera from infected animals.

Conclusions:

  • H. contortus GAPDH possesses a novel function as a complement-binding protein (H.c-C3BP).
  • This protein represents a new class of complement-binding molecules involved in parasite immune evasion.
  • The characterization of H.c-C3BP provides a basis for developing new therapeutics targeting parasite immune modulation.

Keywords:
GAPDHH.c-C3BPH. contortusMACcomplement activityimmunomodulation

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