Background: In immunopathological conditions, clinical diagnosis is commonly made on the basis of patient symptoms, measurement of blood leukocyte levels or proinflammatory biomarkers, non-specific radiological findings and, regarding infection, microbiological analysis. Nevertheless, frequently the exact spatial location of inflammation or even infection cannot be reliably identified, despite the use of up-to-date clinical, laboratory and imaging techniques. For this reason, new tools are warranted for use in advanced diagnosis and therapy targeting in patients.
Objective: The peptide CPCFLLGCC (LLG), known to bind activated β2-integrins in vitro, was fused with green fluorescent protein (GFP) to test the ability of LLG fusions to target and bind activated leukocytes in vivo.
Methods: A murine skin scratch inflammation model was chosen for the convenient non-surgical detection of GFP.
Results: The murine skin lesion inflammation model demonstrated in vivo targeting of LLG-GFP to sites of inflammation. Targeting by LLG-GFP fusion construct depends on the ability of the LLG-moiety to bind activated leukocytes. Control construct unable to bind β2-integrins appeared biologically inert.
Conclusion: The data support the possibility of using this fluorescently labeled peptide as a tool for both the detection of and targeting to inflammatory sites characterized by robust leukocyte activation.