Complement (C′3)-Coated Red Blood Cells Following Infection with the Virus of Equine Infectious Anemia

The pathogenesis of the anemia in 17 horses experimentally infected with the virus of equine infectious anemia (EIA) was investigated. It was demonstrated by direct Coombs' tests that 15 of the animals had C′3 but no IgG, IgM or IgG(T) on their RBC surfaces. Red blood cells from 8 of 10 horses with a positive anti-C′3 Coombs' test were more osmotically fragile than normal. The RBC life spans of 7 horses with C′3 coated RBC ranged from 18 to 90 days (normal 136 ± 17 days). It was concluded that the hemolysis in this virus disease was associated with C′3 coating of RBC.