Figure 6. Effect of gastric mucin on host cell invasion by MT of Y82 and Y30 strains in vitro and in vivo.

A) HeLa cells were incubated with gastric mucin (20 mg/ml) and then metacyclic forms were added. After 1 h incubation, the cells were fixed and Giemsa-stained for intracellular parasite counting. Values are the means ± SD of four independent assays performed in duplicate. The difference in absence and in the presence of gastric mucin was significant for Y30 strain (*p<0.005). B) Balb/c mice were administered orally with metacyclic forms of Y82 strain (n = 5) or Y30 (n = 5). Four days later, the stomachs of mice were collected and the histological sections were stained by hematoxylin and eosin. The number of amastigote nests was counted in 16–18 equivalent tissue sections of the mouse stomach, and the representative results are shown, with bars corresponding to the variation in the number of parasite nests between sections. The difference in parasite numbers between Y82 and Y30 strains was significant (*p<0.0001).