Agglutination of Helicobacter pylori coccoids by lectins

AIM To study the agglutination pattern ofHelicobacter pylori coccoid and spiral forms.METHODS Assays of agglutination andagglutination inhibition were applied usingfifteen commercial lectins.RESULTS Strong agglutination was observedwith mannose-specific Concanavalin A(Con A),fucose-specific Tetragonolobus purpureas(Lotus A)and N-acetyl glucosamine-specificTriticum vulgaris(WGA)lectins.Mannose andfucose specific lectins were reactive with allstrains of H.pylori coccoids as compared to thespirals.Specific carbohydrates,glycoproteinsand mucin were shown to inhibit H.pylorilectin-agglutination reactions.Pre-treatment ofthe bacterial cells with formalin and sulphuricacid did not alter the agglutination patterns withlectins.However,sodium periodate treatment ofbacterial cells were shown to inhibitagglutination reaction with Con A,Lotus A andWGA lectins.On the contrary,enzymatictreatment of coccoids and spirals did not showmarked inhibition of H.pylori-lectinagglutination.Interestingly,heating of H.pylori cells at 60℃ for 1 hour was shown toaugment the agglutination with all of the lectinstested.CONCLUSION The considerable differences inlectin agglutination patterns seen among the twodifferentiated forms of H.pylori might beattributable to the structural changes during theevents of morphological transformation,resulting in exposing or masking some of the sugar residues on the cell surface.Possibility ofvarious sugar residues on the cell wall of thecoccoids may allow them to bind to differentcarbohydrate receptors on gastric mucus andepithelial cells.The coccoids with adherencecharacteristics like the spirals could aid in thepathogenic process of Helicobacter infection.This may probably lead to different clinicaloutcome of H.pylori associated gastroduodenaldisease.