| First Author | Balamayooran G | Year | 2012 |
| Journal | J Immunol | Volume | 189 |
| Issue | 12 | Pages | 5849-59 |
| PubMed ID | 23129755 | Mgi Jnum | J:190969 |
| Mgi Id | MGI:5451108 | Doi | 10.4049/jimmunol.1200585 |
| Citation | Balamayooran G, et al. (2012) Intrapulmonary G-CSF Rescues Neutrophil Recruitment to the Lung and Neutrophil Release to Blood in Gram-Negative Bacterial Infection in MCP-1-/- Mice. J Immunol 189(12):5849-59 |
| abstractText | We previously demonstrated that MCP-1 is important for E. coli-induced neutrophil migration to the lungs. However, E. coli neither disseminates nor induces death in mice. Furthermore, the cell types and the host defense mechanisms that contribute to MCP-1-dependent neutrophil trafficking have not been defined. In this study, we sought to explore the cell types and the mechanisms associated with Klebsiella pneumoniae-mediated MCP-1-dependent neutrophil influx. MCP-1(-/-) mice are more susceptible to pulmonary K. pneumoniae infection and show higher bacterial burden in the lungs and dissemination. MCP-1(-/-) mice also display attenuated neutrophil influx, cytokine/chemokine production, and activation of NF-kappaB and MAPKs following intratracheal K. pneumoniae infection. rMCP-1 treatment in MCP-1(-/-) mice following K. pneumoniae infection rescued impairment in survival, bacterial clearance, and neutrophil accumulation in the lung. Neutrophil numbers in the blood of MCP-1(-/-) mice were associated with G-CSF concentrations in bronchoalveolar lavage fluid and blood. Bone marrow or resident cell-derived MCP-1 contributed to bacterial clearance, neutrophil accumulation, and cytokine/chemokine production in the lungs following infection. Furthermore, exogenous MCP-1 dose dependently increased neutrophil counts and G-CSF concentrations in the blood. Intriguingly, administration of intratracheal rG-CSF to MCP-1(-/-) mice after K. pneumoniae infection rescued survival, bacterial clearance and dissemination, and neutrophil influx in MCP-1(-/-) mice. Collectively, these novel findings unveil an unrecognized role of MCP-1 in neutrophil-mediated host immunity during K. pneumoniae pneumonia and illustrate that G-CSF could be used to rescue impairment in host immunity in individuals with absent or malfunctional MCP-1. |
