Penicillin streptomycin solution 100x

The human colon adenocarcinoma cell line (Caco-2, clone TC7) (Roxström-Lindquist et al., 2005 (link)) was used in the experiments at either differentiated or proliferating state (Passage no. 10–15). Caco-2 cells were cultured in 25 or 75 cm² flasks as well as in chamber slides (Nunc® Lab-Tek® II, Corning, Sigma-Aldrich, MO, USA), all of which were supplied with complete Dulbecco's Modified Eagle Medium (DMEM), containing 10% fetal bovine serum (FBS), 2 mM GlutaMAX (Gibco, Thermo Fisher Scientific, MA, USA), 1x MEM non-essential amino acid solution (Sigma-Aldrich, MO, USA), 1x of penicillin-streptomycin 100x solution (10,000 units penicillin and 10 mg streptomycin/ml) (Sigma-Aldrich, MO, USA). For host-parasite interaction experiments, the FBS in DMEM was replaced with heat inactivated (HI)-FBS (Gibco, Thermo Fisher Scientific, MA, USA) to avoid adverse effects of active serum components on trophozoites' viability. All culture flasks including chamber slides were incubated in humidified 10% CO₂ incubator at 37°C and used for the experiments either upon reaching confluence (i.e., proliferating) or at 21 days post-confluence (i.e., differentiated). Media was changed twice weekly during the differentiation process.

The following reagents were purchased from Thermo Fisher Scientific (Waltham, MA, USA): B-27^® supplement 50x, Fluo-4 AM cell permeant, formaldehyde 37%, GlutaMAX™ supplement, human recombinant epidermal growth factor (EGF), MEM non-essential amino acids solution 100x, N-2 supplement 100x, and phosphate buffered saline 1x (PBS). The following reagents were purchased from Sigma-Aldrich (St. Louis, MO, USA): 2,5-hexanedione, γ-Aminobutyric acid (GABA), bovine serum albumin (BSA), dimethyl sulfoxide (DMSO), Dulbecco’s Modified Eagle Medium (DMEM), endosulfan, methylmercury, penicillin-streptomycin solution 100x, Triton™ X-100, and TWEEN^® 20. Matrigel^® was purchased from Corning (Corning, NY, USA). Fetal calf serum (FCS) was purchased from ATCC (Manassas, VA, USA). Human recombinant fibroblast growth factor basic (bFGF) was purchased from Peprotech (Rocky Hill, NJ, USA). Tetrodotoxin (TTX) was purchased from Tocris Bioscience (Bristol, UK).