Am. J. Trop. Med. Hyg., 73(6), 2005, pp. 1135-1138
Copyright © 2005 by The American Society of Tropical Medicine and Hygiene
SHORT REPORT
MOLECULAR CLONING AND CHARACTERIZATION OF A PUTATIVE BINDING PROTEIN OF BABESIA CABALLI
HIROMI IKADAI*,
YUMI TAKAMATSU,
RYOKO TAKASHIRO,
AYAKA SEGAWA,
NOBORU KUDO,
IKUO IGARASHI, AND
TAKASHI OYAMADA
Department of Veterinary Parasitology, School of Veterinary Medicine and Animal Sciences, Kitasato University, Towada, Aomori, Japan; National Research Center for Protozoan Diseases, Obihiro University of Agriculture and Veterinary Medicine, Obihiro, Hokkaido, Japan
ABSTRACT
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.
Received March 11, 2005.
Accepted for publication July 21, 2005.
Financial support: This study was supported by Grants-in-Aid for Scientific Research and Young Scientists from the Ministry of Education, Culture, Sports, Science and Technology of Japan and the Japan Society for the Promotion of Science, and the Kitasato University Research Grant for Young Researchers.
* Address correspondence to Hiromi Ikadai, Department of Veterinary Parasitology, School of Veterinary Medicine and Animal Sciences, Kitasato University, Towada, Aomori 034-8628, Japan. E-mail: ikadai{at}vmas.kitasato-u.ac.jp
Authors addresses: Hiromi Ikadai, Yumi Takamatsu, Ryoko Takashiro, Ayaka Segawa, Noboru Kudo, and Takashi Oyamada, Department of Veterinary Parasitology, School of Veterinary Medicine and Animal Sciences, Kitasato University, Towada, Aomori 034-8628, Japan. Ikuo Igarashi, National Research Center for Protozoan Diseases, Obihiro University of Agriculture and Veterinary Medicine, Obihiro, Hokkaido 080-8555, Japan.
Reprint requests: Hiromi Ikadai, Department of Veterinary Parasitology, School of Veterinary Medicine and Animal Sciences, Kitasato University, Towada, Aomori 034-8628, Japan, Telephone: 81-176-23-4371, Fax: 81-176-25-0165, E-mail: ikadai{at}vmas.kitasato-u.ac.jp.
Copyright © 2005 by the American Society of Tropical Medicine and Hygiene.