Related Experiment Video
Updated: Jun 23, 2026
Evaluation of the Interplay Between the Complement Protein C1q and Hyaluronic Acid in Promoting Cell Adhesion
Published on: June 15, 2019
Mapping the complement C1q binding site in Haemonchus contortus calreticulin
S Naresha1, A Suryawanshi, M Agarwal
1Division of Biochemistry, Indian Veterinary Research Institute, Izatnagar, UP, India.
Insights
Haemonchus contortus parasite calreticulin (CalR) inhibits host immunity by binding complement C1q. Researchers identified two new C1q binding sites on H. contortus CalR, crucial for understanding host-parasite interactions.
Area of Science:
- Parasitology
- Immunology
- Biochemistry
Background:
- Haemonchus contortus is a significant gastrointestinal parasite affecting domestic animals.
- The parasite releases calreticulin (CalR), a calcium-binding protein that influences the host immune system.
- CalR inhibits the classical complement pathway by interacting with complement C1q protein.
Purpose of the Study:
- To map the specific regions within the N-domain of H. contortus calreticulin responsible for binding to complement C1q.
- To identify novel C1q binding sites on H. contortus calreticulin.
Main Methods:
- Generation of small recombinant fragments of the N-domain of H. contortus calreticulin.
- Utilizing synthetic peptides to probe C1q binding interactions.
- Mapping of C1q binding sites on the N-domain of H. contortus calreticulin.
Main Results:
- Two novel C1q binding sites were identified in the N-domain of H. contortus calreticulin.
- The newly discovered binding sites have sequences GKYYDDAKRD and AKFPKKFT.
- These findings expand upon previously identified C1q binding motifs in human calreticulin.
Conclusions:
- The study reveals multiple C1q binding motifs in H. contortus calreticulin.
- Understanding these interactions is vital for developing strategies to bolster host immune responses against H. contortus.
- The identified motifs provide insights into host-parasite immune modulation mechanisms.
Abstract:
Haemonchus contortus is an economically important gastrointestinal parasite of domestic animals. The parasite secretes calreticulin (CalR), a Ca(++) binding protein which modulates the host immune response. One way by which this protein acts is by inhibiting the classical complement pathway by binding to complement C1q protein. Understanding CalR-C1q interaction is important to develop methods to enhance host immune response. In this study, we have mapped the regions in the N-domain of CalR that facilitates C1q binding by generating small recombinant fragments of the domain and using synthetic peptides. In addition to already identified C1q binding motifs in human CalR, two additional sites in the N-domain of H. contortus were revealed with the following sequences-GKYYDDAKRD and the AKFPKKFT. The significance of multiple C1q binding motifs in CalR is discussed in relation to host-parasite interactions.
