RESUMO
A recombinant protein, rLdccys1, which was produced by expression of the gene encoding a 30 kDa cysteine proteinase from Leishmania (Leishmania) chagasi, was used for detection of antibodies in sera from patients with active visceral leishmaniasis (VL) in enzyme-linked immunosorbent assays. Analysis of the predicted amino acid sequence of rLdccys1 showed that it contains all the characteristics of a cysteine proteinase. The ability of the protein to react with sera from humans with VL was also shown by Western blotting. The sensitivity for detection of specific antibodies to L. (L.) chagasi bodies using rLdccys1, L. (L.) chagasi promastigote lysates, and amastigote lysates was 80%, 98%, and 99%, respectively. No cross-reactivity between rLdccys1 and Chagas disease was observed, and there was little positive reactivity with sera from patients with cutaneous leishmaniasis and tuberculosis, compared with promastigote and amastigote extracts. Our findings indicate that rLdccys1 from L. (L.) chagasi constitutes a potential tool for the diagnosis of American VL.
Assuntos
Anticorpos Antiprotozoários/sangue , Cisteína Endopeptidases/genética , Leishmania/genética , Leishmania/imunologia , Leishmaniose Visceral/diagnóstico , Sequência de Aminoácidos , Animais , Western Blotting , Estudos de Casos e Controles , Cricetinae , Primers do DNA , Ensaio de Imunoadsorção Enzimática , Feminino , Humanos , Leishmaniose Visceral/sangue , Mesocricetus , Dados de Sequência Molecular , Reação em Cadeia da Polimerase , Valor Preditivo dos Testes , Proteínas de Protozoários/genética , Proteínas Recombinantes/genética , Sensibilidade e Especificidade , Testes SorológicosRESUMO
High in vitro lymphoproliferative responses were induced in humans and dogs by a recombinant Leishmania (Leishmania) chagasi cysteine proteinase, with secretion of IFN-gamma in asymptomatic subjects or of IFN-gamma, interleukin 4 (IL-4), and IL-10 in oligosymptomatic subjects. In contrast, responses of symptomatic patients and dogs were lower, with production of IL-4 and IL-10.