HUMORAL AND CELLULAR IMMUNE-RESPONSES TO SYNTHETIC PEPTIDES OF THE LEISHMANIA-DONOVANI KINETOPLASTID MEMBRANE PROTEIN-11

Native kinetoplastid membrane protein-11 (KMP-11), purified from crude extracts of Leishmania donovani parasites, activates T cells from ind ividuals who have recovered from visceral leishmaniasis. In this work we used three 38-mer peptides spanning the amino acid sequence of the L. donovani KMP-11 as solid-phase ligands in enzyme-linked immunosorbe nt assays (ELISAs) and as stimulating antigens in lymphoproliferative assays in order to evaluate humoral and cellular immune responses to w ell-defined sequences of the protein. Antibody reactivity against the three peptides was measured in plasma from 63 Sudanese visceral leishm aniasis patients (VL) and the percentage of patients with anti-KMP-11 antibodies in ELISA were 37% (KMP-11-1), 30% (KMP-11-2) and 58% (KMP-1 1-3). The fraction of VL patients with measurable antibody reactivity in one or more of the three ELISAs was 79%. Cross-reactivity to the KM P-11 peptides was detected in plasma from Sudanese patients suffering from Leishmania major infections and in plasma from Sudanese and Danis h patients infected with Plasmodium falciparum. In lymphoproliferative assays, 10 of 17 PBMC isolates from donors previously infected with L . donovani showed a response to one or more of the three KMP-11 peptid es.