Presence of human serum in vitro enhances NTS viability and induces worm development past the LuS.

NTS were cultured in HM and DMEM supplemented with 200 U/ml Penicillin and 200 μg/ml Streptomycin with or without additional supplementation of 20% HSe. (A) Viability scoring was performed at the indicated time points. The percentage of developmental stages in culture with either (B) HM, (C) HM + 20% HSe, (D) DMEM or (E) DMEM + 20% HSe was calculated for the indicated time points by bright field microscopy. (F) Representative photomicrographs were taken on day 35 post-transformation. Scale bar applies to all shown pictures. Arrowheads indicate dead NTS. Arrows indicate early and late LiS. Each data point is shown as a mean ± SD of pooled data from three independent experiments with three biological replicates each. * p ≤ 0.05, ** p ≤ 0.01, *** p ≤ 0.001 comparing HM with HM + 20% HSe, × p ≤ 0.05, ×× ≤ 0.01, ××× ≤ 0.001 comparing DMEM with DMEM + 20%. HSe, human serum; SkS, skin stage; LuS, lung stage; LiS, liver stage; s.p., score points; p.t., post-transformation. (PZFX)