Candida albicans and c6 astroglial cell interaction. Effect on L-arginine pathway.

FIGUEREDO MAURICIO, RENNA M.SOL, PARAJE GABRIELA, CORREA SILVIA, SOTOMAYOR CLAUDIA.

Córdoba, Argentina

Congreso; VII Latin American Congress of Immunology.; 2005

Asociación Latinoamericana de Inmunología (ALAI) en conjunto con la Sociedad Argentina de Inmunología (SAI), la Sociedad Chilena de Inmunología (SOCHIN), la Sociedad Latinoamericana de Histocompatibilidad (SLAH) y el Grupo de Trabajo de Inmunología Pediát

More than the 50% of  patient who die form systemic candidiasis  show fungal invasion in the central nervous system(CNS). Astrocytes are the most numerous cells type in the brain and can exhibit  immunocompetent  function in response to injury, such as  cytokine release and activation of inducible isoform of nitric oxide synthase(iNOS). This cell has important storage of Arginine, a only substrate of NOS. We evaluate the interaction between rat astroglial line, C6 and C.albicans  using FITC-labeled-fungus for microscopy studies and evaluating the ability of C.albicans to trigger the L-arginine pathway. Astroglial cells were co-cultured with viable C.albicans (10:1 effector-target ratio/ 48h), or with LPS and PMA. Specific enzyme inhibitor or different sugars also were employed. C.albicans triggered the classic pathway of L-arginine, showing a clear expression of iNOS (western blot) and significant production of NO(p vs basal and LPS < 0,01); the expression of the enzyme was blocked  by Aminoguanidine. Interestingly, C.albicans also trigger in the astroglial cells the alternative metabolic pathway of  arginine, activating L-arginase enzyme to produce urea and ornithine. The arginase  activity was notably increased after C.albicans  incubation, five fold increase compared with the control(p<0.01); mannose 30mM partially blocked the activation. C.albicans can interact with astroglial cells and  activate both metabolic pathways. This phenomenon could be important in the immunopathogenesis of CNS candidiasis.