INDUCTION, TRANSCRIPTION, SYNTHESIS, AND ADSORPTION OF INTERLEUKIN-1 BY DIALYZER MEMBRANES

This study was designed to dissect the direct effect of dialyzer membr ane on interleukin-1 (IL-1) induction from those of complement activat ion, mechanical stimulation, acetate/bicarbonate and endotoxin diffusi on, and cell type interactions. To this end, a suspension of P388D1 mu rine macrophages in a complement-free culture medium containing 10% he at-inactivated serum, a closed-loop system consisting of tubing alone or with a hollow-fiber cuprammonium cellulose (CU) or polyacrylonitril e (PAN) dialyzer, and a roller pump were used. The dialysate compartme nt was filled with the same medium and capped. Cell suspension was rec irculated at 300 mL/min for 3 h. Cells and supernates were separated, and adhering proteins were eluted. All samples tested negative for end otoxin. IL-1 mRNA was greatest with CU, followed by PAN and tubing alo ne. IL-1 in the supernate was greater with CU than with either tubing alone or PAN (P < 0.005; analysis of variance), which showed comparabl e values. IL-1 eluted from loops was greatest with PAN dialyzers, foll owed by sets with CU dialyzers and tubing alone (P < 0.001; analysis o f variance). Thus, both CU and PAN membranes directly induce IL-1. How ever, avid adsorption by PAN attenuates the rise in circulating IL-1.