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Updated: Nov 3, 2025
Engineering Antiviral Agents via Surface Plasmon Resonance
Published on: June 14, 2022
A Single-Pass Type I Membrane Protein from the Apicomplexan Parasite Cryptosporidium parvum with Nanomolar Binding
Tianyu Zhang1,2, Xin Gao1, Dongqiang Wang1
1Key Laboratory for Zoonosis Research of the Ministry of Education, College of Veterinary Medicine, Institute of Zoonosis, Jilin University, Changchun 130062, China.
Abstract:
Cryptosporidium parvum is a globally recognized zoonotic parasite of medical and veterinary importance. This parasite mainly infects intestinal epithelial cells and causes mild to severe watery diarrhea that could be deadly in patients with weakened or defect immunity. However, its molecular interactions with hosts and pathogenesis, an important part in adaptation of parasitic lifestyle, remain poorly understood. Here we report the identification and characterization of a C. parvum T-cell immunomodulatory protein homolog (CpTIPH). CpTIPH is a 901-aa single-pass type I membrane protein encoded by cgd5_830 gene that also contains a short Vibrio, Colwellia, Bradyrhizobium and Shewanella (VCBS) repeat and relatively long integrin alpha (ITGA) N-terminus domain. Immunofluorescence assay confirmed the location of CpTIPH on the cell surface of C. parvum sporozoites. In congruence with the presence of VCBS repeat and ITGA domain, CpTIPH displayed high, nanomolar binding affinity to host cell surface (i.e., Kd(App) at 16.2 to 44.7 nM on fixed HCT-8 and CHO-K1 cells, respectively). The involvement of CpTIPH in the parasite invasion is partly supported by experiments showing that an anti-CpTIPH antibody could partially block the invasion of C. parvum sporozoites into host cells. These observations provide a strong basis for further investigation of the roles of CpTIPH in parasite-host cell interactions.
Insights
Researchers identified a Cryptosporidium parvum T-cell immunomodulatory protein homolog (CpTIPH) on the parasite surface. This protein binds to host cells and may play a role in parasite invasion, offering new avenues for therapeutic strategies.
Area of Science:
- Parasitology
- Molecular Biology
- Immunology
Background:
- Cryptosporidium parvum is a significant zoonotic parasite causing diarrheal disease.
- Understanding parasite-host interactions is crucial for developing effective treatments.
- Molecular mechanisms of C. parvum pathogenesis remain largely unknown.
Purpose of the Study:
- To identify and characterize a novel protein involved in Cryptosporidium parvum-host interactions.
- To investigate the function of the identified protein in parasite invasion and host cell binding.
Main Methods:
- Gene identification and protein characterization (CpTIPH).
- Immunofluorescence assays to determine protein localization.
- Binding affinity assays (K_d) to quantify host cell interaction.
- Inhibition assays using anti-CpTIPH antibodies to assess invasion blocking.
Main Results:
- CpTIPH, a type I membrane protein, was identified on the surface of C. parvum sporozoites.
- CpTIPH exhibits high binding affinity to host cells (nanomolar range).
- Antibodies against CpTIPH partially inhibited parasite invasion into host cells.
Conclusions:
- CpTIPH is a surface protein of C. parvum involved in host cell binding and invasion.
- This protein represents a potential target for therapeutic interventions against cryptosporidiosis.
