Wisteria floribunda agglutinin or lectin (WFA/WFL) is isolated from Japanese Wisteria seeds. It is a glycoprotein with a molecular weight of 116 kDa and is composed of four subunits. It has an isoelectric point between pH 5.2 and pH 5.8. This lectin is not blood group specific although it does react stronger with human type A1 cells over A2, B, or O cells. The presence of a sialic acid residue may explain the lectins lack of reactivity. The increased reactivity of neuraminidase treated erythrocytes with WFA supports this conclusion.

WFA contains a strong hemagglutinin activity and is a potent mitogen, both strongly inhibited by GalNAc, although mitogenic activity is also inhibited by N,N-diacetylchitobiose. This lectin has been used to fractionate lymphocyte populations, and although not mitogenic, elicits the production of lymphokines from murine splenocytes.