Title: 0498 - Immune Ushering by Neutrophils Following Aggregatibacter actinomycetemcomitans Infection


David Polak (Presenter)
hadassah medical center - hebrew university

Sharon Shany Kdoshim, hadassah medical center - hebrew university
Lior Shapira, Hebrew University - Hadassah School of Medicine


Objectives: Neutrophils are keystone players in the first line of defense against infection and their impaired function was suggested to be associated to the pathogenesis of aggressive periodontitis (AgP). Emerging data reveal a central role for neutrophils as ushering cells that control immune cell trafficking during infection. The aim of the study was to investigate the role of neutrophils during Aggregatibacter actinomycetemcomitans (Aa) JP2 clone (AgP pathogen) infection.

Methods: Mouse primary neutrophils and splenocytes were harvest and used ex vivo to investigate splenocyte migration toward the secretome of neutrophils following Aa infection. Additionally, Chemokine profiling of neutrophils and splenocytes was compared using proteome analysis. To investigate the role of neutrophils in vivo, subcutaneous chambers were implanted in C57BL/6J mice, followed by infection with Aa. Immunotyping of chamber cells was performed using flow cytometry. The role neutrophils was tested by their depletion prior to infection using a specific Ly6G antibody.

Results: When neutrophils were stimulated ex vivo with Aa, they induced splenocytes migration, and secreted unique chemokines from the CCL and CXCL family that were not expressed in splenocyte` secretome. In vivo, neutrophils were found to be the dominant cell in the immune response during Aa infection. Other immune cells present in the infection site were NKT, monocytes, B and T lymphocytes. Following Ly6G injection, neutrophils were absent from the infection site. Interestingly, all other immune cells were absent from the infection site as well.

Conclusions: Neutrophils were found to play a pivotal role during Aa infection as conductors of the immune response. These cells were found to be a solely responsible for recruitment of other immune cells during the infection. This trait is possibly mediated by a unique chemokine expression profile of neutrophils.

Disclosure Statement:
The submitter must disclose the names of the organizations with which any author have a relationship, the nature of the relationship, and the clinical or research area involved. The following is submitted: NONE