Cytotoxicity Assessment of Peptide EKL1C

Cytotoxicity of peptide EKL1C to cells was assessed as previously described [33 (link)]. Briefly, 50 μL of EKL1C at different concentrations, together with 100 µL of MT-2 cells, CEMx174 517 5.25 M7 cells, or U87 CD4⁺ CCR5⁺ cells (3 × 10⁴ cells/well), was cultured in wells of a 96-well cell culture plate at 37 °C with 5% CO₂ for 48 h. Then, 50 µL Cell Counting Kit-8 (CCK-8; Dojindo, Kumamoto, Japan) was diluted 5× and added, followed by an additional incubation at 37 °C for 4 h. The absorbance was measured at 450 nm by using the Ultra 384 microplate reader (Tecan). Calcusyn software (Biosoft) was used to calculate CC₅₀ of EKL1C, and GraphPad Prism (GraphPad Software) was used to draw the histogram.