DETECTION AND CHARACTERIZATION BY IMMUNOBLOT ANALYSIS OF POTENTIALLY DIAGNOSTIC LEISHMANIA-INFANTUM POLYPEPTIDES IN HUMAN VISCERAL LEISHMANIASIS

Humoral immune responses were studied in 53 sera from 18 patients with visceral leishmaniasis by immunoblot analysis. Sera from visceral lei shmaniasis patients recognized antigens with molecular weights ranging from < 14 kDa to more than 100 kDa. Bands ranging between 49 and < 14 kDa were the most specific. The 40, 33 and 17 kDa antigens were recog nized by 90%, 79% and 79% of the patients sera, respectively. Sera fro m one patient with Chagas' disease identified 8 of 11 antigens of the specific region. Treatment with periodate eliminated the cross-reactio n in three of these antigens (40, 29, 26 kDa). The study of serial ser a collected from the different patients showed a decrease in intensity or dissappearance in some of the diagnostic bands, particularly the 1 7 kDa band. The band of 17 kDa seems to be useful to study the clinica l evolution, for post-treatment control and also for epidemiologic pur poses. (It has been identified in 7% of control sera from endemic area s.) Immunoblot could be a valuable tool in the diagnosis of visceral l eishmaniasis, being move sensitive and specific than other serologic t ests.