EM Non-Essential Amino Acids Solution, 0.1 mM Sodium Piruvate, 10 mM HEPES, 100 U/ml Penicillin 100 ug/ml Streptomycin. At the second passage MEF were plated after trypsinization onto 6 cm dishes, 56105 cells per dish. Next morning, the medium was removed and 8 ml of fresh RPMI containing 56106 Reh or Jurkat cells was added for LTbR activation. After 3 and 24 hours, MEF were washed twice with PBS