Caracterização de frações antigênicas de Leishmania braziliensis e avaliação da resposta imune em pacientes com leishmaniose tegumentar. / Characterization of Leishmania braziliensis antigenic fractions and their immune response in patients with tegumentary leishmaniasis.

AUTOR(ES)
DATA DE PUBLICAÇÃO

2004

RESUMO

Leishmania braziliensis is one of the most important causative agents of American tegumentary leishmaniasis (ATL), an endemic disease in Corte de Pedra, Bahia, Brazil, and in almost 88 other subtropical and tropical countries. Many studies about antigen characterization have been done with soluble leishmania antigens (SLA), but few of them involved native or recombinant L. braziliensis antigens. Some molecules have been described in the literature: high molecular weigh antigens, membrane lipophosphoglycan (LPG), 72, 63, 46, 30, 20, and 11 KDa, as well as histones and heat-shock proteins (HSP). The aim of this study was to factionate L. braziliensis promastigote antigens, and characterize their role in induce cellular and humoral responses. For these proposes, promastigotes obtained from a cutaneous leishmaniasis patient lesion were cultivated in Schneider medium. The extract obtained by sonication was submitted to chromatography using Bio-Gel P-60 colum. Fractions were analyzed by electrophoresis using 10% polyacrylamide, and revealed by silver nitrate. The immunoblotting was done using plasmas from cutaneous leishmaniasis patients. We selected two fractions: F-IV: 64 KDa, and F-V: 64, 47, 32, and 19 KDa, which we used to study cellular immune response. Cytokines (IFN-γ, TNF-α and IL-10) produced by peripheral blood mononuclear cells (PBMC) from 15 cutaneous patients (CL) and 5 mucous patients (MC)were evaluated by ELISA method. The results were: For LC patients: IFN-γ: 180,0233,2 pg/mL (F-VI) and 611,6 603,4 pg/mL (F-V) (p=0,0164); TNF-α: 793,9555,6 pg/mL (F-VI) and 780,3739,7 pg/mL (F-V) (p>0,05) and IL-10: 54,663,5 pg/mL (F-VI) and 35,938,8 pg/mL (F-V) (p>0,05). For LM patients: IFN-γ: 69,264,9 pg/mL (F-VI) and 389,0612,6 pg/mL (F-V) (p>0,05); TNF-α: 583,1637,4 pg/mL (F-VI) and 552,2589,2 pg/mL (F-V) (p>0,05) and IL-10: 22,324,0 pg/mL (F-VI) and 30,950,6 pg/mL (F-V) (p>0,05). PBMC from CL produced high levels of IFN-γ and TNF-α and low levels of IL-10, especially when induced by F-V. In PBMC cultures from ML patients, high levels of Th1 cytokines were also produced, but no statistical difference was observed, and IL-10 production was discretely observed. In this group of patients, the correlation analysis showed that in mononuclear cells stimulated by F-V, IFN-γ contributed significantly to TNF-α production (p=0,037). The serologic reaction revealed that CL plasmas recognized the 64, 32 and, more weakly, 19 KDa proteins. These data suggest a probable active participation of these molecules in inducing cellular response to Leishmaniasis. Furthermore, in ML, this antigen association may contribute to tissue damage and a worst lesion, while in CL this cooperation could be immunoprotective.

ASSUNTO(S)

antígenos leishmaniasis l. braziliensis resposta celular antigens imunologia leishmaniose cellular response l. braziliensis

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