About the Lectin

Specific blood group agglutinins have been isolated from many species of Salvia, two of which are available from EY Laboratories. Salvia sclarea (SSA) and Salvia horminum (SHA), in crude form, are both moderately active blood agglutinins. All Salvia hemagglutinins are inhibited to some degree by N-acetyl-D-galactosamine. SSA is also inhibited by teichoic acids, which are found on the surface of many bacteria 3 . SSA shows a strong preference for α–linked GalNAc 1,2 , and can be purified on a GalNAc-containing affinity matrix 1 . Both SSA and SHA recognize specific blood group antigens associated with the O-linked polysaccharide portion of glycophorin. The Tn antigen, recognized by SSA, is simply a terminal GalNAc linked to serine (or threonine). This condition is due to the absence of the galactosyltransferase required for the formation of normal polysaccharides in glycophorin. SHA also recognizes the Tn antigen as well as the Cad determinant. Cad is a rare, inherited blood group antigen, characterized by an additional side-chain GalNAc residue. Cad has the folowing structure: Neu5Ac α(2,3)[GalNAc β(1,4)] Gal β(1,3) [Neu5Ac α(2,6)] GalNAc α–1-serine (or threonine). The reactivity of SSA and SHA for these blood group antigens would indicate that SSA will bind only to an α–GalNAc, while SHA will recognize both α– and β–GalNAc. It has been reported that the anti-Tn and the anti-Cad activities of SHA can be separated 4 . EY Laboratories has not attempted to isolate these two as separate lectins. SSA, SHA, and the anti-T specific lectin PNA have been used in the identification of erythrocyte polyagglutination 5 . SSA has been used to characterize GalNAc α-O-Ser (Tn) formation in Jurkat T-leukemia cells 6 . EY Laboratories has been able to prepare a purified lectin using techniques other than affinity chromatography. The purified SSA lectin gives a single band slightly greater than 20,000 Da when analyzed by SDS-PAGE.

REFERENCES

  1. Piller, V., et al. (1986) J. Biol. Chem. 261 : 14069-14075.
  2. Piller, V., et al. (1990) Eur. J. Biochem. 191 : 461-466.
  3. Bird, G. W. G. (1973) Proc. Nat. Acad. Sci.
  4. Berger, E. G. and Kozdrowski, I. (1978) FEBS Lett. 93 : 105-108.
  5. Bird, G. W. G. and Wingham, J. (1974) Vox Sang. 26 : 163-166.
  6. Piller, V., et al. J. Biol. Chem. 265 : 9246-9271.

Product Characteristics
Buffer 0.01M Phosphate – 0.15M NaCl, pH 7.2-7.4.
Blood Group Anti-Tn (SSA,SHA); Anti-Cad (SHA).
Activity Less than 5 mg/ml of crude SSA will agglutinate neuraminidase treated human erythrocytes. Less than 2.5 mg/ml of crude SHA will agglutinate neuraminidase treated erythrocytes and untreated type O or A 2 cells. As much as 10 mg/ml of crude SHA may be required to agglutinate type B or A 1 cells.
Inhibitory Carbohydrate Both lectins are nominally specific for N‑acetyl‑D‑galactosamine. Lectin activity is only slightly inhibited by the monosaccharide.
Molecular Weight Purified SSA gives a single band of MW=20,000 by SDS-PAGE.