Figure 2. Characterization of Binding Properties of the SabA Adhesin, and Its siaHA Properties.
(A) A panel of 99 Swedish clinical H. pylori isolates was tested for sia-HA properties and for binding to 125I-sdiLex conjugate. The numbers on the x axis indicate the shifts in HA titers after sialidase treatment: positive values indicate lowered sia-HA titers (i.e., sia-HA, whereas negative values indicate increased HA titers (i.e., sialic acid–independent HA). No change in HA titer is indicated by 0. The y axis gives the percentage of bound sLex-conjugate.
(B) SabA was affinity-adsorbed to erythrocytes from a cell-surface protein extract of strain J99. Immunostaining using SabA antibodies confirmed the presence of SabA adsorbed onto the erythrocyte surfaces as a result of binding to sialylated glycans (lane 1), whereas SabA was completely absent when erythrocytes had been depleted of sialic acid by sialidase treatment prior to the test (lane 2). Molecular weight markers (in kDa) are indicated.
(C) Binding of H. pylori strains J99 and J99sabA to human erythrocyte glycosphingolipids. (i) Chemical detection by anisaldehyde. (ii–iii) Autoradiograms obtained by binding of 35S-labeled H. pylori strain J99 and the J99sabA mutant, respectively, to separated glycosphingolipids. The lanes contain non-acid glycosphingolipids of human erythrocytes, 40 μg (lane 1); gangliosides of human erythrocytes, 40 μg (lane 2); GM3 ganglioside (NeuAcα2–3Galβ4Glcβ1Cer), 4 μg (lane 3); NeuAcα2–3-neolactotetraocylceramide
(NeuAcα2–3Galβ4GlcNAcβ3Galβ4Glcβ1Cer), 4 μg (lane 4); NeuAcα2–6-neolactotetraocylceramide
(NeuAcα2–6Galβ4GlcNAcβ3Galβ4Glcβ1Cer), 4 μg (lane 5); G-10 ganglioside (NeuAcα2–3Galβ4GlcNAcβ6 (NeuAcα2–3Galβ4GlcNAcβ3)Galβ4GlcNAcβ3Galβ4Glcβ1Cer), 1 μg (lane 6); G9-B ganglioside (Galα3(Fucα2)Galβ4GlcNAcβ6
(NeuAcα2–3Galβ4GlcNAcβ3)Galβ4GlcNAcβ3Galβ4Glcβ1Cer), 1 μg (lane 7); and reference gangliotriaosylceramide (GalNAcβ4Galβ4Glcβ1Cer) of mouse feces, 4 μg (lane 8).