IDENTIFICATION OF A 94-KILODALTON ANTIGEN ON LEISHMANIA PROMASTIGOTE FORMS AND ITS SPECIFIC RECOGNITION IN HUMAN AND CANINE VISCERAL LEISHMANIASIS

We have analysed by immunoblotting sera from humans and dogs with visc eral leishmaniasis, from the Old World as well as the New. When lysate s of promastigotes are used as antigens, antibodies against a 94 kDa L eishmania component are detected, regardless of the age and geographic al origin of the patient, the serum antibody titre as measured by indi rect immunofluorescence, and the number of arcs in counterimmunoelectr ophoresis. Low dilutions of sera from patients with Old and New World cutaneous leishmaniasis did not react with the 94-kDa antigen, whateve r the species of Leishmania used as antigens. Sera from patients with other infections than leishmaniases, or without infection, are negativ e, even at low dilution. Anti-94 kDa antibodies were defected in the s era of Leishmania-infected dogs from both the Old and the New World. W hen lysates of leishmania mexicana axenic amastigotes are used as anti gens, the 94-kDa antigen was little or none identified by sera from hu mans and dogs with visceral leishmaniasis, and never recognized by con trol sera. Thus, the specific recognition of the 94-kDa promastigote a ntigen in human and canine visceral leishmaniasis suggests that this a ntigen could be a potential candidate in the differential immunodiagno sis of the disease.