About the Lectin

Crude seed extracts of Wisteria(also spelled Wistaria) contain both a strong hemagglutinin and a potent mitogen. These two activities are both strongly inhibited by GalNAc, although the mitogen is also inhibited by N,N’-diacetylchitobiose ^1,2 . The agglutinin is not blood group specific, but it does react stronger with human type A₁ cells than with A ₂ , B, or O cells. Both the agglutinin and the mitogen have been isolated by using a combination of salt precipitation, ion-exchange chromatography, and gel filtration. The critical step in isolating the agglutinin or the mitogen is the choice of the ion-exchange resin. The use of an affinity chromatography technique developed by EY Laboratories produces an agglutinin which reacts more strongly with erythrocytes than the material prepared using ion-exchange chromatography. The agglutinin reacts more readily with an affinity matrix than does the mitogen; however, the mitogen may co-purify with the agglutinin. This may explain some of the heterogeneity associated with the preparation when analyzed by SDS-PAGE. The affinity purified lectin has not been specifically analyzed for mitogenicity. The purified mitogen is reported to be a relatively weak agglutinin of both erythrocytes and leucocytes ² . Carbohydrate inhibition studies of the mitogen and the agglutinin indicate that they are primarily specific for GalNAc, and that they have a preference for β–linked sugars, although the agglutinin is reactive with α- and β-linked non-reducing GalNAc residues ³ . In a study using WFA in the analysis of glycolipids, radiolabelled WFA bound to the Forssman glycolipid, globoside, and asialo-GM ₂ , but not with GM ₂ itself ⁴ . The presence of a sialic acid residue may explain the lectin’s lack of reactivity. The increased reactivity of neuraminidase treated erythrocytes with WFA supports this conclusion. The purified lectin has been used successfully for characterizing and grouping strains of Campylobacter jejuni and Campylobacter coli ⁵ , as a marker for mammalian cell transformation ⁶ , as a marker for perineuronal nets ensheathing neurons of the mammalian neocortex ^7,8 , changes of specific glycoproteins after cortical ischemia ⁹ , and in characterizing GalNAc-terminating glycoproteins in mammary glands in different states of location ^10,11 . A similar lectin has also been isolated from Wistaria sinensis ¹² .

REFERENCES

1. Kurokawa, T., et al. (1976) J. Biol. Chem. 251 : 5686-5693.
2. Toyoshima, S., et al. (1971) Biochemistry. 10 : 4457.
3. Pillar, V., et al. (1990) Eur. J. Biochem. 191 : 461-466.
4. Torres, B. V., et al. (1988) Arch. Biochem. Biophys. 262 : 1-11.
5. Wong, K. H., et al. (1986) J. Clin. Micro. 23 : 407-410.
6. Tsuda, M., et al. (1975) Gann: Japanese J. Cancer Res. 66 : 513-521.
7. Hartig, W., et al. (1992) Neuroreport 3 : 869-872.
8. Seeger, G., et al. (1996) J. Hirnforschung 37 : 351-366.
9. Wu, A.M., et al. (1998) Neuroscience 82 : 397-420.
10. Sato, T., et al. (1997) J. Biochem. 122 : 1068-1073.
11. Sakiyama, T., et al. (1998) Biochim. Biophys. Acta.
12. Ahmed, H. and Chatterjee, B.P. (1988) Carbohyd. Res. 177 : 173-183.