Biochemical characterization and vaccine potential of a heme-binding glutathione transferase from the adult hookworm Ancylostoma caninum.

Abstract

We report the cloning and expression of Ac-GST-1, a novel glutathione S-transferase from the adult hookworm Ancylostoma caninum, and its possible role in parasite blood feeding and as a vaccine target. The predicted Ac-GST-1 open reading frame contains 207 amino acids (mass, 24 kDa) and exhibited up to 65% amino acid identity with other nematode GSTs. mRNA encoding Ac-GST-1 was detected in adults, eggs, and larval stages, but the protein was detected only in adult hookworm somatic extracts and excretory/secretory products. Using antiserum to the recombinant protein, Ac-GST-1 was immunolocalized to the parasite hypodermis and muscle tissue and weakly to the intestine. Recombinant Ac-GST-1 was enzymatically active, as determined by conjugation of glutathione to a model substrate, and exhibited a novel high-affinity binding site for hematin. The possible role of Ac-GST-1 in parasite heme detoxification during hemoglobin digestion or heme uptake prompted interest in evaluating it as a potential vaccine antigen. Vaccination of dogs with Ac-GST-1 resulted in a 39.4% reduction in the mean worm burden and 32.3% reduction in egg counts compared to control dogs following larval challenge, although the reductions were not statistically significant. However, hamsters vaccinated with Ac-GST-1 exhibited statistically significant worm reduction (53.7%) following challenge with heterologous Necator americanus larvae. These studies suggest that Ac-GST-1 is a possible drug and vaccine target for hookworm infection.

• Authors: Bin Zhan, Sen Liu, Samirah Perally, Jian Xue, Ricardo Fujiwara, Peter Brophy, Shuhua Xiao, Yueyuan Liu, Jianjun Feng, Angela Williamson, Yan Wang, Lilian L Bueno, Susana Mendez, Gaddam Goud, Jeffrey M Bethony, John M Hawdon, Alex Loukas, Karen Jones, Peter J Hotez
• Journal: Infection and immunity (Infect Immun) Vol. 73 Issue 10 Pg. 6903-11 (Oct 2005) ISSN: 0019-9567 [Print] United States
• PMID: 16177370 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Carrier Proteins
• Heme-Binding Proteins
• Hemeproteins
• RNA, Messenger
• Vaccines
• Glutathione Transferase

Topics

• Amino Acid Sequence
• Ancylostoma (enzymology, immunology)
• Ancylostomiasis (prevention & control)
• Animals
• Carrier Proteins (analysis, genetics, immunology)
• Cloning, Molecular
• Cricetinae
• Dogs
• Glutathione Transferase (analysis, genetics, immunology)
• Heme-Binding Proteins
• Hemeproteins (analysis, genetics, immunology)
• Larva (enzymology)
• Molecular Sequence Data
• RNA, Messenger (analysis, metabolism)
• Vaccines (genetics, immunology)