Submitted to: Journal of Biological Chemistry
Publication Type: Peer reviewed journal
Publication Acceptance Date: 12/1/2013
Publication Date: 12/30/2013
Publication URL: http://handle.nal.usda.gov/10113/58993
Citation: Matsubayashi, M., Sasai, K., Kimata, I., Shigehiko, U., Iseki, M., Lillehoj, H.S., Matsuda, H., Tani, H., Baba, E. 2013. Elongation Factor-1a is a novel protein associated with host cell invasion and a potential protective antigen of Cryptosporidium parvum*. Journal of Biological Chemistry. 288(47):34111-20. doi: 10.1074/jbc.M113.515544. Interpretive Summary: Cryptosporidiosis is a parasitic infection of humans and animals, including livestock and poultry, and a novel intervention strategy is needed to reduce economic losses caused by this infection. In this report, ARS scientist collaborated with scientists at Osaka University to identify a novel protein within the parasite that could be used as a target to develop a new vaccine for Cryptosporidiosis. Scientists identified a protein designated as EF-1a and additional studies revealed that EF-1a was important for parasite survival, movement and the invasion of intestinal cells. Furthermore, the protein was present in other parasites that infect poultry and cause another intestinal disease, Coccidiosis. The results indicate that EF-1a is a potential vaccine candidate and further studies are necessary to better apply the use of the protein in the development of a vaccine against the parasites causing Cryptosporidiosis and Coccidiosis in animals and humans.
Technical Abstract: The phylum Apicomplexa comprises obligate intracellular parasites that infect vertebrates. All invasive forms of Apicomplexa possess a unique complex of organelles at the anterior end, referred to as the apical complex, which is involved in host cell invasion. Previously, we generated the chicken monoclonal antibody (mAb) 6D-12-G10 against an apical cytoskeleton antigen of E. acervulina sporozoites. The antigen was highly conserved among Apicomplexan parasites including other Eimeria spp., Toxoplasma, Neospora and Cryptosporidium. In the present study, we identified the apical cytoskeleton antigen of Cryptosporidium parvum (C. parvum)and further characterized its potential as a target molecule against cryptosporidiosis. By indirect immunofluorescence, reactivity of mAb 6D-12-G10 was similar with those of anti-ß- and anti-'-tubulins on C. parvum sporozoites, and by immunoelectron microscopy the antigen was ultrastructurally located both on the surface and underneath the inner membrane at the apical region of zoites. The 6D-12-G10 mAb significantly inhibited in vitro host cell invasion by C. parvum. MALDI-TOF/MS and LC-MS/MS analysis of its tryptic peptides showed that the protein reactive with mAb 6D-12-G10 is elongation factor-1a (EF-1a). These results indicate that C. parvum EF-1a play a role in mediating host cell entry by the parasite and, as such, could be a candidate vaccine antigen against cryptosporidiosis.