Isolation of a human erythrocyte-adapted substrain of Babesia rodhaini and analysis of the merozoite surface protein gene sequences.
Babesia rodhaini is a rodent hemoparasite closely related to B. microti, the major causative agent of human babesiosis. We tested the infectivity of B. rodhaini for human erythrocytes by using the SCID mouse model in which the circulating erythrocytes were replaced with those of humans. Initially, parasites grew very poorly in the mouse model, but a variant capable of propagating in human erythrocytes emerged after an adaptation period of three weeks. In an attempt to identify parasite proteins involved in the alteration of host cell preference, an expression cDNA library of B. rodhaini was constructed and screened with immune mouse sera. Although we were able to obtain three merozoite surface protein (MSP) genes, sequences of these genes from both the parental strain and human erythrocyte-adapted substrain were identical. Our results suggest that B. rodhaini has potential ability to infect human erythrocytes, but development of this ability may not be brought about by an amino acid change in MSPs.
Kawabuchi
Takako
T
School of Veterinary Medicine, Rakuno-Gakuen University, Ebetsu, Japan.
Tsuji
Masayoshi
M
Kuwahara
Satoko
S
Nishida
Atsumi
A
Shimofurutachi
Tadahisa
T
Oka
Hideki
H
Ishihara
Chiaki
C
D000220:Adaptation, Biological / Q000235:genetics*; D000818:Animals; D001403:Babesia / Q000235:genetics* / Q000472:pathogenicity; D001483:Base Sequence; D017931:DNA Primers; D004912:Erythrocytes / Q000469:parasitology*; D015723:Gene Library; D006801:Humans; D007106:Immune Sera; D051379:Mice; D016513:Mice, SCID; D008969:Molecular Sequence Data; D015800:Protozoan Proteins / Q000235:genetics* / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D017421:Sequence Analysis; D017422:Sequence Analysis, DNA
D017931:DNA Primers; D007106:Immune Sera; D015800:Protozoan Proteins