Narcissus pseudonarcissus lectin or agglutinin (NPL/NPA) is affinity purified composed of four subunits. It agglutinates rabbit erythrocytes but is non-reactive with human erythrocytes. NPA has an isoelectric point between pH 4.2 and pH 4.6 with a specific binding activity toward Î±-D-mannose, although studies have suggested that the purified lectin may have greater affinity for internal mannosyl residues than for nonreducing terminal units. A buffer washed column elutes the sugar Î±-methylmannoside.Human studies have found NPA to be nearly non-mitogenic, but it has been reported through an in vitro study that mitogenicity of NPA is age-related, with lymphoproliferative response of peripheral blood mononuclear cells (PBMC) in umbilical cord blood has a sevenfold increase than adult blood. NPA has also been found to be mitogenic for PBMC from lambs and not adult sheep.Texas Red is a red-fluorescent dye and when bound to Narcissus pseudonarcissus Lectin (NPL/NPA) can show the binding pattern of this lectin in cellular imaging applications. There is very little overlap between the emission spectra of Texas Red and FITC making this combination ideal for dual-labeling experiments. Rhodamine dyes, such as Texas Red, are more photostable and less sensitive to pH change when compared to other dyes such as fluorescein.