Infectious Bursal Disease Virus Internalization Involves A Macropinocytic Pathway

MARÍA CECILIA GIMENEZ; JOSÉ F. RODRÍGUEZ; MARÍA ISABEL COLOMBO; LAURA RUTH DELGUI

Buenos Aires

Otro; Reunión Anual de la Sociedad Argentina de Investigaciones en Bioquímica y Biología Molecular; 2013

Sociedad Argentina de Investigaciones en Bioquímica y Biología Molecular

The Infectious Bursal Disease Virus (IBDV) causes an immunosuppressive disease in birds, causing economic losses in the poultry area worldwide. We studied the viral entry pathway and found that internalization occurred in a clathrin-, caveolin-, cholesterol- and dynamin independent pathway, so we aimed our study on the macropinocytic pathway. We examined the effect of actin polymerization inhibitors in IBDV infection employing Western blot and Confocal Microscopy techniques. Subsequently, we assessed the effect of a Na+/H+ exchanger selective inhibitor involved in the formation of macropinosomes. Furthermore, ultrastructural analysis was performed to analyse viral internalization kinetics and the effect of actin polymerization inhibitors on IBDV entry by transmission electron microscopy. We found that the actin cytoskeleton integrity and a functional NHE-1 are required for IBDV infection. Moreover, the ultrastructural analysis revealed cell membrane structures associated with virus entry morphologically compatible with formation of macropinosomes. In addition, when actin polymerization was inhibited, we observed morphological changes that support the notion that the macropinocytosis is used by the virus to be endocytosed by cells. Together, these data strongly indicate that the IBDV uses the macropinocytic pathway as the main mechanism of cell internalization.