Cells and cell culture
Primary human fetal foreskin fibroblast cells (HFFFs) immortalised with human telomerase (HFFF-TERTs) were maintained in Dulbecco’s modified Eagle’s medium (DMEM) supplemented with 10% v/v foetal bovine serum (FBS), 100 U/ml penicillin, and 100 μg/ml streptomycin at 37 °C with 5% CO2 (DMEM/FBS/PS). HFFF-TERTs have been tested at regular intervals since isolation to confirm that human leukocyte antigen (HLA) and MHC Class I Polypeptide-Related Sequence A (MICA) genotypes, cell morphology and antibiotic resistance are unchanged.