EXTRACTION OF HAEMOPROTEUS-COLUMBAE (HAEMOSPORINA, HAEMOPROTEIDAE) ANTIGEN FROM ROCK DOVE PIGEONS (COLUMBA-LIVIA) AND ITS USE IN AN ANTIBODY ELISA

Erythrocytic stages of Haemoproteus columbae were extracted from the c ytoplasm of nucleated red blood cells (RBC) of Rock dove pigeons (Colu mba livia) using cationic detergent (N,N'N'-polyoxyethylene(10)N-tallo w-1 ,3-diaminopropane [EDTA-20]) and discontinuous Percoll gradient de nsity. Crude RBC extract (CRBCE) antigen was prepared. Parasitized RBC s were more resistant to EDTA-10 action than unparasitized cells. An e nzyme-linked immunosorbent assay (ELISA) was developed for detection o f anti-H. columbae immunoglobulins in 30 wild-captured C. livia. Whole blood, serum, and dried blood on filter paper gave similar results; t he latter was selected for sampling convenience. Optimal antigen conce ntration was 5 mu g/ml, and anti-H. columbae immunoglobulins were dete ctable at a 10(-4.11) dilutions. The binding efficacy of anti-chicken IgG to the pigeon immunoglobulins was significantly higher than anti-d uck IgG or anti-turkey IgG. Parasitemia by Giemsa-stained thin blood s mears ranged from 20.0 to 47.5%, (x) over bar = 32.4 +/- 8.3%; 17 of 3 0 birds had multiply infected RBCs with a mean parasitemia of 2.4 +/- 1.1%, range 0.7-4.9%; 27 birds were positive by the ELISA. No clinical signs of infection were observed. ELISA absorbance values were not co rrelated with the level of parasitemia in individual birds. All pigeon s were negative for anti-Plasmodium relictum and anti-P. elongatum imm unoglobulins as determined by ELISA. The pigeons were not subclinicall y infected with Plasmodium spp. as determined by inoculation of domest ic ducklings with blood from dexamethasone-immunosuppressed pigeons.