CaracterizaÃÃo de um antÃgeno com motivos repetitivos de Leishmania chagasi

AUTOR(ES)

Alessandra Lima de Albuquerque

DATA DE PUBLICAÇÃO

2004

RESUMO

Visceral Leishmaniasis (VL) is an endemic parasitic infection widespread in the world that in Brazil it is caused by Leishmania chagasi. It is an important cause of morbidity and mortality, in part because of significant difficulties in its diagnosis and treatment. Control of VL therefore requires research aiming the characterization of antigens which can be used for both the diagnosis and as component of vaccines against this disease. In earlier work we identified by immunoscreening of a L. chagasi amastigote cDNA library several clones coding for proteins containing long stretches of tandem repeats. One of these proteins, named LC 14, codes for 22 copies of a 14 amino-acids (aas) repeat. A homologue from L. major has also been identified containing over 100 copies of the 14 aas repeat plus a very similar C-terminus. Here we start the functional characterization of this protein in L. chagasi by subcloning its cDNA and expression in Escherichia coli. The recombinant protein was used for production of specific rabbit polyclonal antiserum. Western-blotting of total L. chagasi extract with the specific antibody produced multiple bands, several of which with molecular weights higher than 170kDa. A different profile is observed in L. major extract, with a reduced number of bands, although several bands with high molecular weights can also be observed. In both L. braziliensis and Trypanosoma cruzi the recognition by the antibody is impaired, and in the latter only a minor band is detected, indicating that these antigens are not very conserved within the order Kinetoplastida and even within the Leishmania genus. Further work will be required to understand the reason for the multiple protein bands recognized by the antibody as well as the proteinâs function and intracellular localization in L. chagasi

ASSUNTO(S)

microorganismos leishmaniose visceral leishmania genÃtica molecular antÃgenos genetica

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