Seek and Destroy: The use of the MAFIA mouse to track and eliminate In vivo endogenous Macrophages and Dendritic cells during Immunological Responses in the Eye.

Abstract

Abstract: : Purpose: To visualize in vivo the recruitment of inflammatory cells into the eye and selectively eliminate endogenous macrophages and dendritic cells. Methods: Recruitment of EGFP macrophages and dendritic cells was monitored in the cornea of MAFIA mice (macrophage fas induced apoptosis) using intravital microscopy and 3D confocal analysis of whole mount corneas. MAFIA mice express EGFP and the cytoplasmic domain of fas in all endogenous macrophages and dendritic cells under the control of the CFMS promoter. In vivo depletion of macrophages and dendritic cells was induced with systemic administration of a synthetic dimerizer and monitored in vivo in the eye. Corneal inflammation was induced by intrastromal injection of LPS and recruitment of EGFP cells was monitored at different time points. Results: EGFP–positive macrophages and dendritic cells were detected in the cornea by 24 hours after LPS injection in non–depleted mice and this population of cells significantly increased by 48 hours. 3D confocal analysis confirmed the presence of EGFP–positive cells in the stroma with distinct dendritic morphology. In contrast, the MAFIA mice depleted systemically with the synthetic dimerizer had no EGFP–positive cells in LPS injected cornea. Conclusions: The recruitment pattern of endogenous macrophages and dendritic cells to an inflammatory signal can be visualized in the eye of MAFIA mice in vivo. More importantly, systemic depletion eliminates these cells and makes the MAFIA mouse a unique model to elucidate the immunological role of macrophages and dendritic cells in the eye.

Keywords: immunomodulation/immunoregulation • inflammation • immune tolerance/privilege