Albumin nitrosylated by activated macrophages possesses antiparasitic effects neutralized by anti-NO-acetylated-cysteine antibodies.

摘要: Activated macrophages exert an L-arginine-dependent cytostatic effect on the extracellular parasite, Trypanosoma musculi. This is not observed in absence of albumin culture medium but restored by addition albumin, indicating presence albumin-nitric oxide (NO) adduct acting as effector molecule. Since L-cysteine represents a privileged target for NO, immunochemical approach was performed using acetylated-cysteine-BSA conjugate. conjugate nitrosylated sodium nitrite NO donor. Binding to conjugated haptens assayed spectrophotometry. It completely abolished mercuric chloride, confirming S-NO bond. Polyclonal Abs were obtained after immunizing rabbits with S-nitroso-acetylated-cysteine (NO-ac-Cys) conjugates. Using enzyme-linked immunosorbent assay method, Ab avidity and specificity determined competition experiments between NO-ac-Cys-conjugated compounds other or non-nitrosylated compounds. The resulting cross-reactivity ratios showed that NO-ac-Cys-BSA best recognized compound. These used vitro study kinetics NO-derived from activated murine macrophages. Anti-NO-ac-Cys inhibited antimicrobial T. Moreover, antiparasitic activity supernatants Calmette-Guerin bacillus-activated required also anti-NO-ac-Cys Ab, showing role S-nitroso-albumin.