Characterisation of the gene encoding a protective antigen from Babesia microti identified it as eta subunit of chaperonin containing T-complex protein 1.
Passive immunisations with a monoclonal antibody termed 1-5H showed a partial but significant inhibition of parasitaemia against Babesia microti challenge infection. By immunoscreening with 1-5H, a clone (termed p58 gene) was obtained from a cDNA expression library of B. microti and the complete nucleotide sequence was determined. A protein homology search showed significant amino acid identities to the eta subunit of the chaperonin containing T-complex protein 1 (CCT) of human (59%), mouse (58%) and Plasmodium falciparum (62%). Genomic analyses indicated that the p58 gene is present as a single copy gene and contains a total of approximately 400-bp introns in the genome of B. microti. The mAb 1-5H recognised a 58-kDa protein of B. microti and was found to cross-react with a 60-kDa protein of Babesia rodhaini. These results suggest the possibility that the p58 protein is the CCT eta subunit of B. microti and functions as a chaperonin.
Nishisaka
M
M
National Research Center for Protozoan Diseases, Obihiro University of Agriculture and Veterinary Medicine, Inada-cho, Obihiro, Hokkaido 080-8555, Japan.
Yokoyama
N
N
Xuan
X
X
Inoue
N
N
Nagasawa
H
H
Fujisaki
K
K
Mikami
T
T
Igarashi
I
I
D000595:Amino Acid Sequence; D000818:Animals; D000911:Antibodies, Monoclonal / Q000096:biosynthesis / Q000276:immunology; D000953:Antigens, Protozoan / Q000235:genetics* / Q000276:immunology; D001403:Babesia / Q000235:genetics* / Q000276:immunology; D001404:Babesiosis / Q000276:immunology / Q000628:therapy; D001483:Base Sequence; D056404:Chaperonin Containing TCP-1; D018833:Chaperonins / Q000235:genetics* / Q000276:immunology; D004591:Electrophoresis, Polyacrylamide Gel; D005260:Female; D019084:Fluorescent Antibody Technique, Indirect; D015723:Gene Library; D007116:Immunization, Passive; D051379:Mice; D008807:Mice, Inbred BALB C; D008969:Molecular Sequence Data; D018512:Parasitemia / Q000276:immunology / Q000628:therapy; D016133:Polymerase Chain Reaction; D017386:Sequence Homology, Amino Acid
D000911:Antibodies, Monoclonal; D000953:Antigens, Protozoan; C533315:Tcp1 protein, mouse; D056404:Chaperonin Containing TCP-1; D018833:Chaperonins