XI International Meeting on Paracoccidioidomycosis

XI International Meeting on Paracoccidioidomycosis

Resume:92-3

Poster (Painel)

92-3

Effects of Silencing of PbGp43, the Major Immunogenic Exoantigen of Paracoccidioides brasilienisis

Authors:

Isaura Torres Gomez (BCM, CIB - Molecular and Cellular Biology UnitU DE A, MEDELLIN, CO - Biology Institute, U de Antioquia, Medellin, Colombia) ; Orville Hernandez Ruiz (BCM, CIB - Molecular and Cellular Biology UnitU DE A, MEDELLIN, CO - Biology Institute, U de Antioquia, Medellin, Colombia) ; Jose F Munoz (BCM, CIB - Molecular and Cellular Biology UnitU DE A, MEDELLIN, CO - Biology Institute, U de Antioquia, Medellin, Colombia) ; Diana Tamayo (BCM, CIB - Molecular and Cellular Biology UnitU DE A, MEDELLIN, CO - Biology Institute, U de Antioquia, Medellin, Colombia) ; Ana Maria Garcia (BCM, CIB - Molecular and Cellular Biology Unit) ; Oscar Mauricio Gomez (BCM, CIB - Molecular and Cellular Biology Unit) ; Sonrisa Posada (BCM, CIB - Molecular and Cellular Biology Unit) ; Angela Restrepo (BCM, CIB - Molecular and Cellular Biology Unit) ; Juan G Mcewen (BCM, CIB - Molecular and Cellular Biology UnitU DE A, MEDELLIN, CO - Facultad de Medicina, U de Antioquia, Medellin, Colombia)

Abstract

The major antigen secreted by P. brasiliensistext is a 43–kDa glycoprotein (gp43); some functions have been attributable to this exoantigen as to participate in evasion mechanisms during the installation of primary infection, stimulate granulome formation in vitro, presents T-cell epitopes that induce protective response against the fungus and as a ligand to extracellular matrix protein specially laminin and fibronectin. In this work, we used a P. brasiliensistext Pb339 with down regulation in gene expression of PbGP43 (PbGP43-aRNA). No morphological changes neither alteration in viability or cell vitality were observed in PbGP43-aRNA strain; however a decrease in the bind capacity to laminin and fibronectin was observed in the cell free antigen obtained of this cells in comparison with antigens obtain from PbWt as demonstrated by affinity ligand assays. In addition, we observed a significant reduction in the cell viability of PbGP43-aRNA yeast cells after incubation with activated macrophages; which is related with the role previously described to gp43, and related with the evasion of immune system. Interestingly, we found a possible immuno-modulatory effect of gp43 in the release of TNFα by activated macrophages during interaction with PbGP43 aRNA yeast cells. In summary, we demonstrated two important roles described to gp43: first, the role in cell defense against macrophage, possibly related with evasion mechanism for the primary line of immune defense, and second as a ligand to laminin and fibronectin important extracellular matrix protein involved in fungal adhesion to host tissues. Acknowledgement: Colciencias project No 221340820447; Corporación para Investigaciones Biológicas and Universidad de Antioquia supported this work. The National Doctoral Program of COLCIENCIAS supported Isaura Torres and Orville Hernández.

Keyword: Paracoccidioides brasiliensis, PbGP43, Extracellular matrix protein, Macrophages, Silencing

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