Characterization of an Ostertagia ostertagi annexin-like protein at different developmental stages

Authors: Tuo, Wenbin; SHARMA, POOJA - Non ARS Employee; TUO, JAMES - University Of Maryland Eastern Shore (UMES); Jenkins, Mark; Zarlenga, Dante; XIAO, ZHENGGUO - University Of Maryland Eastern Shore (UMES); Fetterer, Raymond

Submitted to: Parasitology Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/29/2017
Publication Date: 3/29/2017
Publication URL: http://handle.nal.usda.gov/10113/5726150
Citation: Tuo, W., Sharma, P., Tuo, J., Jenkins, M.C., Zarlenga, D.S., Xiao, Z., Fetterer, R.H. 2017. Characterization of an Ostertagia ostertagi annexin-like protein at different developmental stages. Parasitology Research. 116:1515-1522.

Interpretive Summary: Ostertagiosis remains to be one of the economically important parasitic diseases in cattle in the temperate regions of the US. The long term goal of this research is to develop an alternative approach for the control of this disease. We know that young calves can be infected by the parasites repeatedly, but no protection is developed. We hypothesize that the parasite must produce proteins that can suppress host immune response. Annexins belong to a large family of proteins and some of the members have the ability to suppress immune responses. Multiple annexin-like genes were found in the parasite O. ostertagi. This study characterized one of the most abundant members of annexin-like proteins. We cloned, expressed, and purified the Ostertagia annexin-like protein and produced antibodies to this protein. Using this antibody, most of the Ostertagia annexin-like proteins were immunolocalized to the hypodermis of the adult worm. These results were confirmed by Western blotting that the adult worm had the overall highest annexin-like proteins in the worm homogenates. we propose that this protein can be a potential vaccine candidate for the adult stage of O. ostertagi in cattle.

Technical Abstract: Ostertagiosis remains to be one of the economically important parasitic diseases in cattle in the temperate regions in the US and worldwide. It is known that repeated exposures to Ostertagia ostertagi in calves cause significant pathology in the stomach, but elicit little protective immunity. The Ostertagia larvae use the host's gastric glands as a niche for development, where the parasite completes its parasitic stages from infective L3 to late L4 larvae or young adult when they exit the gastric glands. While in the gastric glands, the parasitic larvae must cross-regulate the host by down-regulating the host immune responses. We hypothesized that proteins of the annexin (ANX) family may be involved in host-parasite interactions during ostertagiosis. BLASTN search with the bovine ANX A1 identified 2 families of Oos-ANX like proteins (Oos-ANXL), each of which was highly conserved at the genetic level and identical at the amino acid sequence level with various deletions. Oos-ANXL1 had 2 copies and Oos-ANXL2 had 20 copies of transcripts. The present study characterized an Oos-ANXL2 protein which represents the most abundant Oos-ANXL that was further defined as Oost-ANXL2.1 and 2.2 (with 22 aa deletion) with a predicted signal peptide. Only Oos-ANX2.2 with a coding sequence of 519 bp was PCR-amplified, cloned and expressed. Oos-ANXL2.2 was immunolocalized to both L3 and adult, but not L4. The staining appeared to be associated with the gut or hypodermis in L3, but it was specifically associated with hypodermis and to a lesser extent the gut in adult worm. Western blotting detected 3 bands of proteins in parasite homogenates by the anti-oos-ANXL2.2 antibody. Integrated optical density for each of the 3 bands or the total Oos-ANXL (P<0.05) was higher in adult worm than in L3 or L4. The Oos-ANXLs appeared to be most abundant in the adult worm and could be a potential vaccine candidate against infection by adult stage of O. ostertagi in cattle.