Indirect immunostaining of formalin-fixed paraffin embedded human tonsil section with anti-λ light chain (dilution 1 : 200; green) and mouse anti-κ light chain (cat. no. 346 011, dilution 1 : 200; red). Immunoreactive structures on B-cells have been revealed with fluorochromated secondary antibodies. Nuclei have been visualized by DAPI staining (blue).