Antigenic components of partially purified antigens of Leishmania donovani infantum recognized by sera from dogs with asymptomatic or active visceral leishmaniasis.

The antigenic components of a semipurified fraction of Leishmania donovani infantum were determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and Western blot analysis using 14 serum samples from dogs with symptomatic visceral leishmaniasis and 11 serum samples from apparently healthy dogs collected in an area endemic for canine visceral leishmaniasis (CVL). It was found that these antigens were composed of many polypeptides, among which seven components recognized by symptomatic CVL sera, had molecular weights of approximately 18, 28, 30, 33, 63, 70, and 72 kilodaltons (kD); two components of 63 and 70 kD were recognized by three of 11 healthly dog sera. These findings suggest that specific antigens induce humoral immune response in dogs with asymptomatic or active visceral leishmaniasis. Infected dogs are not readily identifiable by their symptoms. The potential interest of the immunoblot test for CVL diagnostic purposes is discussed.