Subsequently, sections were stained with the appropriate fluorescently labelled secondary antibody and Hoechst dye (Invitrogen, #H3570, 1:2,000) / PBS for 1 h at RT and mounted with DAKO mounting medium. (nature.com)
The best way is to ensure that each of the primary antibodies is generated from a different species, in order that the fluorescent - labeled secondary antibodies used will then be detected through separate channels. (ptglab.com)
Background may derive from sticky soluble immune complexes or from contaminating bovine IgG sticking non-specifically and attracting cross-reacting labeled secondary antibodies. (jireurope.com)