Serum from Theileria sergenti-infected cattle accelerates the clearance of bovine erythrocytes in SCID mice.
Anemia is a major clinical sign of Japanese bovine theileriosis caused by Theileria sergenti. To investigate the possible factors causing anemia in cattle, we developed a clearance test for bovine erythrocytes (Bo-RBC) in severe combined immunodeficient (SCID) mice. Clearance of Bo-RBC in the SCID mice was significantly accelerated when the mice were inoculated with a serum sample obtained from an infected calf during a highly parasitized phase but not when they were injected with a serum sample obtained during the convalescence phase. Acceleration of the clearance of Bo-RBC was also observed in mice treated with merozoite extract. Furthermore, the clearance of Bo-RBC that had been treated with merozoite extract was accelerated. A significant hemolytic activity in infected serum (highly parasitized phase) was observed. Activities sufficient to accelerate the clearance of Bo-RBC in SCID mice and to induce in vitro hemolysis of Bo-RBC were also observed with a merozoite extract from T. sergenti. The results suggest a possible linkage between the in vitro hemolysis of Bo-RBC and the acceleration of Bo-RBC clearance in SCID mice.
Hagiwara
K
K
School of Veterinary Medicine, Rakuno Gakuen University, Hokkaido, Japan.
Tsuji
M
M
Ishihara
C
C
Tajima
M
M
Kurosawa
T
T
Takahashi
K
K
D000208:Acute Disease; D000740:Anemia / Q000209:etiology; D000818:Animals; D001681:Biological Assay / Q000379:methods*; D002417:Cattle; D003289:Convalescence; D004905:Erythrocyte Aging; D017707:Erythrocyte Transfusion; D051379:Mice; D016513:Mice, SCID; D013801:Theileriasis / Q000097:blood*; D013997:Time Factors