Figure 3
From: Induction of virulence factors in Giardia duodenalis independent of host attachment
Results for the effects of HSF on adherence and host-cell attachment during co-incubation.
The 3 treatments are as follows: trophozoites in serum-free DMEM in the first round followed by co-incubation with HT-29 (Con/CI), trophozoites exposed to HSF in serum-free DMEM and then co-incubated with HT-29 in the presence of HSF in the second round (HSF/CI) and a control of serum free DMEM in both rounds of the assay (Con/Con). Trophozoites were transferred from the first round of adherence to the second round of co-incubation. (A) Rates for adherence during the first 6 hours between trophozoites co-incubated in T75 flasks containing serum-free DMEM (Con/CI, Con/Con) and trophozoites incubated in the presence of HSF (HSF/CI). A ‘*’ indicates a significant difference in % attached trophozoites (designated by p-value ≤ 0.05). Rates of adherence in HSF-exposed trophozoites were statistically significantly lower at all 3 timepoints compared to unexposed trophozoites. (B) Images depicting the differences in density of adhered trophozoites in HSF-exposed and HSF-free flasks after 6 hours of incubation. Flasks shown were seeded with the same number of trophozoites. (C) Rates of host-cell attachment in the second 6 hours of the assay. Rates of host-cell attachment between trophozoites exposed to HT-29 monolayers (Con/CI) are compared to trophozoites incubated with HT-29 monolayers in the presence of HSF (HSF/CI). A control for adherence was also performed in triplicate in serum DMEM without HT-29 cells. A ‘*’ indicates a significant difference in percentage of attached trophozoites compared to control (designated by p-value ≤ 0.05). Rates of attachment in HSF-exposed cells was significantly lower at all time points between both the control for adherence and the rate for host-cell attachment in unexposed trophozoites. The number of attached trophozoites co-incubated with HT-29 monolayers without HSF was statistically significantly higher compared to the control for trophozoite adherence in flasks only after 6 hours incubation.
