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    Anticorpos monoclonais dirigidos a antígenos lipídicos estágio-específicos de formas promastigotas de Leishmania (Leishmania) amazonensis
    (Universidade Federal de São Paulo (UNIFESP), 2006-12-31) Peder, Leyde Daiane de [UNIFESP]; Straus, Anita Hilda [UNIFESP]; Universidade Federal de São Paulo (UNIFESP)
    In order to obtain information about the lipid expression of promastigote forms of Leishmania (Leishmania) amazonensis, the parasites lipid composition profile was analyzed during log and stationary phase. Two monoclonal antibodies (mAb) termed LST-1 and LST-2 were produced, characterized and used in this study. Promastigote phospholipid expression on log and stationary growth phases were analyzed by high performance thin layer chromatography (HPTLC). At either phase the total lipid extract of L. (L.) amazonensis promastigotes presents phosphatidylinostol (PI), phosphatidylserine (PS), phosphatidylcholine (PC) phosphatidylethanolamine (PE), Lyso- PI and inositol phosphorylceramide (IPC). IPC was characterized by GC/MS, and it was detected sphingosine (d18:1) and fatty acids, mainly palmitic acid (C16:0), and stearic acid (C18:0). It was noted that the molar proportions of IPC, PS, PE and Lyso-PI increased during the culture time, while the percentage of PI and PC decreased. Unlikely, the glycolipid chromatographic profile did not change during the promastigotes growth at log and stationary phases. The mAbs LST-1 and LST-2 were produced against a glycolipid and IPC enriched fraction purified from promastigote forms of L. (L.) amazonensis. Both antibodies are IgM. By HPTLC immunostaining it was demonstrated that mAb LST-1 recognized an acidic lipid component, eluted with 0.2 M of sodium acetate from DEAE-Sephadex column. The LST-1 reactive component presents: i) chromatographic migration characteristic of IPC, ii) is resistant to alkaline hydrolysis; iii) is stained with Dittmer-Lester reagent. On the other hand, the mAb LST-2 was reactive with the glycolipid fraction not retained in DEAE-Sephadex column, and this fraction was visualized on HPTLC by primuline and orcinol/H2SO4 staining. By indirect immunofluorescence, both antibodies showed high reactivity with L. (L.) amazonensis promastigotes. Parasites delipidation with isopropanol:hexane:water (55:20:25; v/v/v), abolished the mAbs reactivity, indicating that the antigens recognized by LST-1 and LST-2 are present exclusively in the lipid fraction. MAb LST-1 did not react with non-fixed parasites, suggesting that IPC is cryptic in the membrane, and maybe localized only in the inner leaf of plasma membrane. Contrasting, mAb LST-2, showed a strong reactivity with live L. (L.) amazonensis promastigotes, also parasite agglutination was observed, indicating that the glycolipids recognized by LST-2 are in parasite surface. By indirect immunofluorescence with LST-1 and LST-2 no reactivity was observed with amastigotes isolated from L. (L.) amazonensis infected hamsters, conversely axenic amastigotes showed a strong fluorescence with both mAbs. By HPTLC it was verified that the lipid fractions of promastigotes, axenic amastigotes and amastigotes isolated from footpad lesions, presented distinct glycolipids and phospholipids profiles. Amastigotes isolated from lesions are rich in glycosphingolipids, whereas axenic amastigotes and promastigotes present glycoinositolphospholipids (GIPLs) recognized by LST-2, and IPC recognized by mAb LST-1. The LST-1 antibody recognized promastigotes from all species of analyzed, and also T. cruzi epimastigotes. It was determined that LST-1 recognizes specifically IPC in these parasites, and it was established that the inositol residue and the ceramide are essential for LST-1 reactivity. By indirect immunofluorescence with mAb LST-2 a strong labeling of only L. (L.) amazonensis promastigotes and axenic amastigotes was observed. LST-2 recognizes 4 glycolipid components termed a, b, c and d, which correspond to GIPLs. It was demonstrated that the carbohydrate moiety is fundamental for LST-2 reactivity. L. (L.) amazonensis promastigotes infected macrophages showed by indirect immunofluorescence, that promastigotes during the macrophage adhesion/infection, secrete or transfer GIPLs recognized by mAb LST-2 to the macrophage. Strong fluorescence in infected macrophage was observed in the first hours of infection. During the next hours of infection (up to 4 hours) also small fluorescent vesicles were observed in the infected macrophages, which did not correspond to phagossomes containing parasites. Thus, these studies describe distinct (glyco)phospholipid profile in lesion amastigotes, axenic amastigotes and promastigotes, and GIPLs vesicles formation during macrophage infection by promastigotes.