Rapid Depletion of Intratumoral Regulatory T Cells Induces Synchronized CD8 T- and NK-cell Activation and IFNγ-Dependent Tumor Vessel Regression.

Regulatory T cells (Tregs) are known to inhibit antitumor immunity, yet the specific mechanism by which intratumoral Tregs promote tumor growth remains unclear. To better understand the roles of intratumoral Tregs, we selectively depleted tumor-infiltrating Tregs using anti-CD25-F(ab') near-infrared photoimmunotherapy. Depletion of tumor-infiltrating Tregs induced transient but synchronized IFNγ expression in CD8 T and natural killer (NK) cells.

Effect of charge localization on the in vivo optical imaging properties of near-infrared cyanine dye/monoclonal antibody conjugates.

Near-infrared (NIR) fluorophores show superior in vivo imaging properties than visible-light fluorophores because of the increased light penetration in tissue and lower autofluorescence of these wavelengths. We have recently reported that new NIR cyanine dyes containing a novel C4'-O-alkyl linker exhibit greater chemical stability and excellent optical properties relative to existing C4'-O-aryl variants. In this study, we synthesized two NIR cyanine dyes with the same core structure and charge but different indolenine substituents: FNIR-Z-759 bearing a combination of two sulfonates and two quaternary ammonium cations, and FNIR-G-765 bearing a combination of two sulfonates and two guanidines, resulting in zwitterionic charge with distinct cationic moieties.

Role of Fluorophore Charge on the In Vivo Optical Imaging Properties of Near-Infrared Cyanine Dye/Monoclonal Antibody Conjugates.

Near-infrared (NIR) fluorophores have several advantages over visible-light fluorophores, including superior light penetration in tissue and lower autofluorescence. We recently demonstrated that a new class of NIR cyanine dyes containing a novel C4'-O-alkyl linker exhibit greater chemical stability and excellent optical properties relative to existing C4'-O-aryl variants. We synthesized two NIR cyanine dyes with the same core structure but different indolenine substituents: FNIR-774 bearing four sulfonate groups and FNIR-Z-759 bearing a combination of two sulfonates and two quaternary ammonium cations, resulting in an anionic (-3) or monocationic (+1) charge, respectively.