Identification of a 148-kDa surface lectin from Giardia lamblia with specificity for α-methyl-?-mannoside

Abstract

A lectin specific for alpha-methyl-D-mannoside was purified from the membrane extract of Giardia lamblia by a combination of gel filtration chromatography on Sephadex G-75 and Superose 6-HR 10/30. The homogeneity of the lectin was established by sodium dodecyl sulfate polyacrylamide gel electrophoresis. The molecular mass of the native protein was 148 kDa. The lectin agglutinated rabbit erythrocytes in the presence of Ca2+ at 37 degrees C and pH 7.0. The maximum activity of the lectin was obtained after trypsin treatment. The inhibition study clearly suggests that the binding site of the lectin recognizes alpha-methyl-D-mannoside as the immunodominant sugar.

Biochemical and immunological characterization of soluble antigens of Giardia lamblia

“…These discrepancies in the protein polymers may be due to the dierent strains and methods used for antigen preparation. The molecular masses of some of the present polypeptides correlated well with previously reported ventral-disc cytoskeleton proteins, giardin (Holberton et al 1988;Alonso and Peattie 1992), heat-shock proteins (Gupta et al 1994), cysteine-rich proteins (Adam 1991;Nash 1992), and surface proteins containing lectin activity of Giardia trophozoites (Sreenivas et al 1995). However, the biological activity of these polypeptides could not be established in the present investigation.…”

“…During the last decade, some surface and internal proteins related to speci®c function have been identi®ed (Crossley and Holberton 1983;Agarwal et al 1988;Gupta et al 1994;Lujan et al 1995;Sreenivas et al 1995). However, no common antigen has been reported that could help in improving the diagnosis as well as in inducing protective immunity against giardiasis.…”

Mimicking microbial strategies for the design of mucus-permeating nanoparticles for oral immunization

“…The glycocalyx consists in long filaments of diverse glycoproteins and glycolipids well attached to the cell surface of enterocytes as a thin but very robust and compact layer (15)(16)(17)(18)(19)(20)(21)(22)(23)(24)(25)(26)(27)(28)(29)(30) lm thick in the small intestine and around 100 lm in the large intestine). In fact, this layer would be able to detain any macromolecule above 30 nm [14].…”

“…The evolutionary adaptation to mucosa is such that mucins are chemoattractants for Campylobacter [23] and the bacterium binds avidly to them through specific ligands, including lipopolysaccharide (LPS) [24,25]. Similarly, the intestinal pathogenic protozoa Cryptosporidium parvum and Giardia duodenalis express surface lectins to adhere to the intestinal mucins [26,27]. In a similar way, H. pylori attaches to mucin carbohydrates by the blood-group antigen-binding and the sialic acid binding adhesins at neutral pH.…”