RESUMO
BACKGROUND: Leishmaniasis defines a cluster of protozoal diseases with diverse clinical manifestations. The visceral form caused by Leishmania donovani is the most severe. So far, no vaccines exist for visceral leishmaniasis despite indications of naturally developing immunity, and sensitive immunodiagnostics are still at early stages of development. METHODOLOGY/PRINCIPLE FINDINGS: Establishing a proteome-serological methodology, we mapped the antigenicity of the parasites and the specificities of the immune responses in human leishmaniasis. Using 2-dimensional Western blot analyses with sera and parasites isolated from patients in India, we detected immune responses with widely divergent specificities for up to 330 different leishmanial antigens. 68 antigens were assigned to proteins in silver- and fluorochrome-stained gels. The antigenicity of these proteins did not correlate with the expression levels of the proteins. Although some antigens are shared among different parasite isolates, there are extensive differences and no immunodominant antigens, but indications of antigenic drift in the parasites. Six antigens were identified by mass spectrometry. CONCLUSIONS/SIGNIFICANCE: Proteomics-based dissection of the serospecificities of leishmaniasis patients provides a comprehensive inventory of the complexity and interindividual heterogeneity of the host-responses to and variations in the antigenicity of the Leishmania parasites. This information can be instrumental in the development of vaccines and new immune monitoring and diagnostic devices.
Assuntos
Antígenos de Protozoários , Leishmania donovani/imunologia , Leishmaniose Visceral/imunologia , Leishmaniose Visceral/parasitologia , Adolescente , Adulto , Sequência de Aminoácidos , Animais , Anticorpos Antiprotozoários/sangue , Especificidade de Anticorpos , Antígenos de Protozoários/genética , Antígenos de Protozoários/isolamento & purificação , Western Blotting , Criança , Eletroforese em Gel Bidimensional , Mapeamento de Epitopos , Feminino , Humanos , Índia , Leishmania donovani/genética , Masculino , Pessoa de Meia-Idade , Dados de Sequência Molecular , Proteoma , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz , Adulto JovemRESUMO
Sera of kala-azar patients from Bihar, India, were used to identify Leishmania donovani antigens encoded by a phage expression library. Ten antigens were identified, five of which have not been described as leishmania antigens before. The antigens specifically react with sera of leishmania-infected patients but not of toxoplasma- or plasmodium-infected patients.