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Institute for Research in Biomedicine
Istituto di Ricerca in Biomedicina

Via Vincenzo Vela 6 - CH-6500 Bellinzona
Tel. +41 91 820 0300 - Fax +41 91 820 0302 - info [at] irb [dot] usi [dot] ch

Role of neutrophils in the immune response to virus and bacteria

Research area: Infection and Immunity

Group leaders: Santiago F. González

Status: In progress

Despite their abundance and physiological importance not much is known about the role of the neutrophils in the lymph node. Different studies have indicated their important function as major effector cells in controlling infections caused by different types of pathogens. Their mechanism of action is based on the secretion of cytokines and the generation of reactive oxygen species and/or microbiocidal peptides directed towards the pathogen. In addition, some studies have suggested a regulatory role, affecting CD8 T cell priming or interacting with dendritic cells (DC). Interestingly, a recent study has observed a competitive role for the antigen between the neutrophils and the antigen presenting cells (macrophages and DC) in the lymph node. In this work, the authors conclude that neutrophils have an important negative role in the CD4 T cell and B cell responses to three protein antigens: hen egg white lysozyme, ovoalbumin and listeriolysin. In a pilot study we observed that the injection of influenza virus was accompanied with a significant increase of infiltrated neutrophils in the subcapsular sinus area of the drained lymph node. Interestingly, we observed that the infiltrated neutrophils were located in the proximity of the subcapsular sinus macrophages. The aim of this project is to characterize the migration patterns of the infiltrated neutrophils in vivo in the lymph node using different infectious models. In addition, we will evaluate the relevance of this cell type in the initiation of the protective response against different pathogens. To achieve this goal we will use Intravital 2-photon-laser microscopy.









2-Photon intravital microscopy snapshots of infiltrated neutrophils (blue) in the SCS area associated subcapsular sinus macrophages (green). Neutrophils accumulate into the SSM area using a swarming mechanism. (D), Schematic model showing the recruitment of neutrophils in the SCS area.