Comparative immunogenicity of Haemaphysalis longicornis and Rhipicephalus (Boophilus) microplus calreticulins.
The ticks Rhipicephalus (Boophilus) microplus and Haemaphysalis longicornis are blood-sucking ectoparasites of bovines, causing serious damages to the livestock production. The main control method for these ticks is based on acaricides. However, the use of vaccines has been studied as a promising control strategy. Calreticulin (CRT) is a multifunctional, predominantly intracellular protein present in almost all cells of animals. The secretion of CRT during feeding might be linked to the modulation of the parasite-host interaction. In the present study, recombinant CRTs of R. microplus (rBmCRT) and H. longicornis (rHlCRT) were expressed in Escherichia coli and purified by ion exchange chromatography and used for the immunization of bovines and mouse. ELISA demonstrated that both rCRTs are recognized by the sera of immunized bovines. In silico, despite the difference in amino acid sequences, antigenic index analysis of HlCRT and BmCRT using the Jameson-Wolf algorithm indicated that both proteins were very similar in antigenicity index, although six different epitopes between the tick CRTs have been inferred. These data were corroborated by competitive ELISA analyses, which suggest the presence of different epitopes within the proteins. Western blot analyses showed that anti-rBmCRT and anti-rHlCRT bovine sera also recognized the native proteins in larvae extracts and, moreover, sera of bovines immunized with saliva and extract of salivary glands recognized both recombinant CRTs. Thus, mouse and bovine immune system recognized rCRTs, resulting in the production of antibodies with similar specificity for both recombinant proteins, although different epitopes could be distinguished between rBmCRT and rHlCRT.
Parizi
Luís Fernando
LF
Centro de Biotecnologia, Universidade Federal do Rio Grande do Sul, Avenida Bento Gonçalves, 9500, Prédio 43421, Porto Alegre 91501-970, RS, Brazil.
Rech
Herbert
H
Ferreira
Carlos Alexandre Sanchez
CA
Imamura
Saiki
S
Ohashi
Kazuhiko
K
Onuma
Misao
M
Masuda
Aoi
A
Vaz
Itabajara da Silva
Ida S
D000818:Animals; D037282:Calreticulin / Q000145:classification* / Q000235:genetics / Q000276:immunology*; D002417:Cattle; D003001:Cloning, Molecular; D003198:Computer Simulation; D005786:Gene Expression Regulation; D018884:Ixodes / Q000502:physiology*; D051379:Mice; D010802:Phylogeny; D011994:Recombinant Proteins
D037282:Calreticulin; D011994:Recombinant Proteins