Antigenic identification of excretory-secretory products of adult Dirofilaria immitis.

Excretory-secretory (ES) products collected from adult Dirofilaria immitis cultured in vitro were analyzed by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and immunoblotting. ES products of male (M-ES) and female (F-ES) worms were separated into 16 and 21 bands by SDS-PAGE with Coomassie blue and silver staining, respectively. The antigenic bands were then analyzed by immunoblotting, using pooled sera from dogs that had naturally contracted D. immitis. Sera from dogs with microfilaremic infection showed 7 bands in M-ES and 10 bands in F-ES, while those from dogs with occult infection revealed 3 bands in M-ES and 10 bands in F-ES. Among these bands, those of 14, 18, 21, 22, 29, and 32 kilodaltons (Kd) were common to M-ES and F-ES, those of 39 and 44 Kd were specific to M-ES, and those of 20, 38, 43, 53, 63, 90, 110, 125 and 136 Kd were specific to F-ES.