Expression of type I and type II TNFR in memory, naive, and GC B lymphocytes. Cells were stained with 10 μg/mL htr-9 (anti-TNFR I), 10 μg/mL utr-1 (anti-TNFR II) MoAbs or an isotype-matched irrelevant MoAb (control) and analyzed by flow cytometry. The FACS profiles are from one representative experiment of the four performed. RT-PCR analysis of TNFR gene expression in GC B cells is shown on the right (M = marker; lane 1 = negative control; lanes 2 through 4 correspond to three different GC B-cell samples). The size of the expected fragments is indicated on the left.