TNF-α expression in B6.GT mice. (A) RNA was purified from 10⁶ FACS sort-purified murine spleen IgM⁺ B cells, CD3⁺ conventional T cells, or IgM⁻CD3⁺B220⁺ DN T cells, or from peritoneal exudate cells (PEC), for assessment of TNF-α, TRAIL, FasL, and GAPDH mRNA levels by conventional semiquantitative RT-PCR. Data shown are representative of 2 independently repeated PCR analyses for each mRNA. (B) Serum TNF-α protein assessed by ELISA assay and quantitated relative to a recombinant murine TNF-α as a standard, with the limit of detection of TNF-α protein of approximately 10 pg/mL (line). Data shown are representative of an independently repeated TNF-α ELISA.