Molecular characterization of a Leishmania donovanii cDNA clone with similarity to human 20S proteasome a-type subunit

Using plasma from patients infected or previously infected with Leishmania donovanii, we isolated a L. donovanii cDNA clone with similarity to the pro teasome a-type subunit from humans and other eukaryotes, The cDNA clone, de signated LePa, was DNA sequenced and Northern blot analysis of L. donovanii poly(A(+))mRNA indicated the isolation of a full length cDNA clone with a transcript size of 1.9 kb. The expressed recombinant LePa fusion protein in duced proliferation of peripheral blood mononuclear cells in one out of sev en patients who had suffered from visceral leishmaniasis. Plasma from 16 ou t of 25 patients with visceral leishmaniasis and four out of 18 patients wi th cutaneous leishmaniasis contained IgG antibodies which reacted with the purified LePa fusion protein as evaluated in an ELISA. The LePa DNA sequenc e was inserted into an eukaryotic expression vector and Balb/c mice were va ccinated. DNA vaccination of Balb/c mice with LePa generated an initial sig nificant reduction in lesion size after challenge. (C) 2000 Elsevier Scienc e B.V. All rights reserved.