(A) Schematic representation of hypothetical patterns of MEDLE2 export in C. parvum. (B) Immunofluorescence assay (IFA) of wild type (WT) and MEDLE2-HA sporozoites fixed on poly-L-lysine-treated coverslips. We note that MEDLE2-HA is not observed in sporozoites. Red, hemagglutinin (HA)-tagged protein; green, sporozoite antigen Cp23; blue, Hoechst. (C) HCT-8 cells infected with MEDLE2-HA parasites were fixed in 30 min increments and processed for IFA. Data shown are representative images from a time-course bridging 3 hr (no observed MEDLE2-HA) and 6 hr (MEDLE2-HA abundant in host cell). White arrowheads denote parasite nuclei. Red, HA-tagged protein; blue, Hoechst. (D) MEDLE2-HA parasites were excysted and used to infect HCT-8 and after 3 hr media were supplemented with brefeldin A (BFA) (10 µg/mL). 10 hr post infection, cells were fixed and processed for IFA. Red, HA-tagged protein; green, parasites (VVL); blue, Hoechst (D). (E) The impact of BFA treatment on MEDLE2-HA export was quantified showing a significant reduction in MEDLE2 export when comparing BFA-treated (red) and untreated cells (blue) (n = 191 untreated, n = 98 treated; mean ± SEM; p<0.0001; unpaired t test with Welch’s correction).
Figure 3—source data 1. Numerical data used for the quantification of HA positive host cells in the absence and presence of Brefeldin A (BFA).