Time course of CD15-induced increase in cytokine mRNA levels. RNA from control MM6 cells (1 × 106 cells) or MM6 cells cross-linked for various times (1 to 4 hours) was analyzed as in Fig 4. For each experiment, control tubes in which reverse transcriptase or RNA was excluded gave no signal after amplification, documenting the absence of contamination. The competitor concentrations used were 10−20 mol/L for TNF-α, 10−20mol/L for IL-1β, and 10−20mol/L β-actin. Thirty cycles of PCR were performed and the PCR amplified products were analyzed by agarose gel electrophoresis. β-Actin served as a negative control. Increased steady-state mRNAs were calculated using zero time as a reference. Shown is a representative experiment of four separate experiments with similar results.
