Bioactive TNF was determined as previously described16 (
link), using TNF sensitive fibroblast cell line WEHI 164, clone 13 (Walter and Eliza Hall Institute). WEHI cells were cultured in
RPMI (Sigma, Germany) containing 10%
FCS (Gibco, Invitrogen Corporation, Germany), 10 U/ml
penicillin (Gibco, Germany), 10 μg/ml
streptomycin (Gibco, Invitrogen Corporation, Germany) and 0.5× amino acid supplement (MEM Amino acids without L-glutamine, Gibco, Germany) at 37 °C with 5% CO
2. Confluent cells were reseeded at 2 × 10
5 cells/ml in
96 well tissue culture plates (Nunclon, Denmark). TNF standards (recombinant mouse TNF, BD PharMingen, San Diego) in 2 fold serial dilutions or samples were added to WEHI cells and incubated for 18 h at 37 °C with 5% CO
2.
MTT solution (2 mg/ml, Sigma, Germany) was then added and incubated for a further 2 h, after which, the supernatants were aspirated and 50 μl DMSO was added and samples were read at 570 nm using VERSAmax Tunable Microplate Reader (Molecular devices Coorporation, California, USA). Data was analyzed using SoftMax Pro (Molecular devices Coorporation, California, USA).
Dambuza I.M., Keeton R., Hsu N.J., Allie N., Quesniaux V.F., Ryffel B, & Jacobs M. (2016). Persistent p55TNFR expression impairs T cell responses during chronic tuberculosis and promotes reactivation. Scientific Reports, 6, 39499.