Expression of Babesia equi merozoite antigen 1 in insect cells by recombinant baculovirus and evaluation of its diagnostic potential in an enzyme-linked immunosorbent assay.
The gene encoding the entire Babesia equi merozoite antigen 1 (EMA-1) was inserted into a baculovirus transfer vector, and a recombinant virus expressing EMA-1 was isolated. The expressed EMA-1 was transported to the surface of infected insect cells, as judged by an indirect fluorescent-antibody test (IFAT). The expressed EMA-1 was also secreted into the supernatant of a cell culture infected with recombinant baculovirus. Both intracellular and extracellular EMA-1 reacted with a specific antibody in Western blots. The expressed EMA-1 had an apparent molecular mass of 34 kDa that was identical to that of native EMA-1. The secreted EMA-1 was used as an antigen in an enzyme-linked immunosorbent assay (ELISA). The ELISA differentiated B. equi-infected horse sera from Babesia caballi-infected horse sera or normal horse sera. The ELISA was more sensitive than the complement fixation test and IFAT. These results demonstrated that the recombinant EMA-1 expressed in insect cells might be a useful diagnostic reagent for detection of antibodies to B. equi.
Xuan
X
X
National Research Center for Protozoan Diseases, Obihiro University of Agriculture and Veterinary Medicine, Inada-cho, Obihiro, Hokkaido 080-8555, Japan.
Larsen
A
A
Ikadai
H
H
Tanaka
T
T
Igarashi
I
I
Nagasawa
H
H
Fujisaki
K
K
Toyoda
Y
Y
Suzuki
N
N
Mikami
T
T
D000818:Animals; D000913:Antibodies, Protozoan / Q000032:analysis; D000953:Antigens, Protozoan / Q000032:analysis / Q000235:genetics; D001403:Babesia / Q000235:genetics / Q000302:isolation & purification*; D001404:Babesiosis / Q000175:diagnosis / Q000276:immunology / Q000662:veterinary*; D002460:Cell Line; D004797:Enzyme-Linked Immunosorbent Assay; D004912:Erythrocytes / Q000469:parasitology; D019084:Fluorescent Antibody Technique, Indirect; D017125:Genes, Protozoan; D005822:Genetic Vectors; D006734:Horse Diseases / Q000175:diagnosis* / Q000276:immunology / Q000469:parasitology; D006736:Horses; D008565:Membrane Proteins / Q000032:analysis* / Q000235:genetics; D051379:Mice; D017924:Nucleopolyhedroviruses; D016133:Polymerase Chain Reaction; D015800:Protozoan Proteins / Q000032:analysis* / Q000235:genetics; D011994:Recombinant Proteins / Q000032:analysis; D018411:Spodoptera
D000913:Antibodies, Protozoan; D000953:Antigens, Protozoan; C085964:EMA-1 protein, Babesia equi; D008565:Membrane Proteins; D015800:Protozoan Proteins; D011994:Recombinant Proteins