Surface reaction of Leishmania: I. Lectin-mediated agglutination

A panel of lectins was used to determine surface sugar residues on promastigotes of twelve isolates of Leishmania, grouped on the basis of their excreted factor (EF) serotype. Inhibiting sugars were used to determine the specificity of the lectins. Serotype A reacted with soybean agglutinin, indicating a specificity for N-acetyl-D-galactosamine, while B serotypes lacked this determinant. Subserotype A₂ was differentiated by its greater reactivity to Concanavalin A, specific for α-D-glucose and α-D-mannose. Ricinus agglutinin, specific for β-D-galactose and N-acetyl- galactosamine, gave the strongest reactions with the A¹ and B¹ subserotypes. The mixed sub-serotypes, A₂B₂ and A₃B₂, were differentiated by peanut agglutinin, which is specific for galactose. Wheat germ agglutinin and Phytohaemagglutinin-P did not agglutinate the promastigotes of any of the strains tested.