[The preparation of an anti-A reagent from the lectin of hairy vetch (Vicia villosa) for detecting antigen A in human erythrocytes and saliva].

Anti-A reagent for the detection of the relevant antigen in human red cells and saliva has been developed. The reagent is prepared by dissolution of purified Vicia villosa lectin in the serum of group AB or B diluted 8 times with PBS. This solvent appreciably improves the anti-A selectivity of lectin and is used for titration. Purification of lectin by ammonium sulfate precipitation is described. The reagent agglutinates group A red cells in the minimal lectin concentration of 2.5 to 10 micrograms/ml and does not agglutinate group 0 and B red cells in concentration 10 mg/ml. Moreover, the reagent is fit for the detection of antigen A in traces of blood and saliva by the absorption-elution method.