Short report: molecular cloning and characterization of a putative binding protein of Babesia caballi.
A composite 2,206 nucleotide DNA sequence encoding a putative immunoglobulin-binding protein (BiP) was constructed from a sequence obtained from Babesia caballi cDNA library clones. The 1,962 nucleotide open reading frame predicts a 72 kD protein with extensive homology with BiPs from Apicomplexa parasites. The BiP gene had a predicted N-terminal signal sequence of 18 amino acids and a C-terminal tetrapeptide sequence (Ser-Asp-Glu-Leu) for signaling in the endoplasmic reticulum lumen. The recombinant protein expressed in baculovirus showed an apparent mass of 72 kD, which is identical to that of the native B. caballi protein. Monoclonal antibodies (MAbs) against B. caballi BiP reacted strongly with extracellular merozoites, but not in early intraerythrocytic stage. Detailed observation showed that the reaction of MAbs against pear-shaped forms was markedly irregular, with either no reaction, or reaction with one or two brightly fluorescent pear-shaped forms (two parasites) of B. caballi.
Ikadai
Hiromi
H
Department of Veterinary Parasitology, School of Veterinary Medicine and Animal Sciences, Kitasato University, Towada, Aomori, Japan. ikadai@vmas.kitasato-u.ac.jp
Takamatsu
Yumi
Y
Takashiro
Ryoko
R
Segawa
Ayaka
A
Kudo
Noboru
N
Igarashi
Ikuo
I
Oyamada
Takashi
T
D000818:Animals; D001403:Babesia / Q000235:genetics*; D001404:Babesiosis / Q000469:parasitology*; D001483:Base Sequence; D003001:Cloning, Molecular; D017931:DNA Primers; D018076:DNA, Complementary / Q000235:genetics; D000091342:Endoplasmic Reticulum Chaperone BiP; D006360:Heat-Shock Proteins / Q000235:genetics*; D006736:Horses; D007143:Immunoglobulin Heavy Chains / Q000235:genetics*; D018832:Molecular Chaperones / Q000235:genetics*; D008969:Molecular Sequence Data; D016133:Polymerase Chain Reaction
D017931:DNA Primers; D018076:DNA, Complementary; D000091342:Endoplasmic Reticulum Chaperone BiP; D006360:Heat-Shock Proteins; D007143:Immunoglobulin Heavy Chains; D018832:Molecular Chaperones