Imaging of cell surface antigens on tumor lymph-node sections using fluorescence quantum dots

In this work we explored the potential of quantum dots for fluorescent detection of lymphoid surface antigens. To optimize detection with quantum dots, we upgraded a fluorescent microscope that allowed us obtaining multiple images from different quantum dots on a single section. Specimens stained with quantum dots remained stable over two weeks and practically did not bleach under the mercury lamp during scores of minutes. Double staining of frozen sections with direct conjugates of quantum dots with primary mouse monoclonal antibodies demonstrated direct conjugate high specificity and sensitivity. High stability of quantum dots' fluorescence allows their use in diagnostics to analyze antigen coexpression on lymphoid tissue sections. "Spillover" of fluorescent signals from quantum dots into adjacent fluorescent channels maximally separated by 40 nm did not exceed 8%, which renders spectral compensation unnecessary.