LPS-desensitized DC fail to acquire CD83 expression: restoration by TNF-α plus PGE2. DC were cultured for 5 days in the presence or absence of LPS at the concentrations indicated (primary culture). Day-5 DC were recultured with or without LPS (10 ng/mL) or PGE2 (10 μmol/L) plus TNF-α (1,000 U/mL) for 48 hours and cells were analyzed for CD83 expression (bold line) by flow cytometry. The isotype control (IgG2b) is also presented (dotted line).