Cytokine production in whole bloodex vivo

Abstract

Interleukin-1β (IL-1β) and tumor necrosis factor-α (TNF-α) have been reported to contribute to the pathogenesis of many inflammatory diseases, e.g., rheumatoid arthritis. As monocytes are believed to be the primary source of these cytokines in peripheral blood, the present study was conducted to establish ranges and patterns of IL-1β and TNF-α secretion. Using heparinized unseparated whole blood obtained from normal human volunteers, peripheral blood monocytes were stimulated withSal. minnesota LPS or BSA/anti-BSA immune complex-coated beads (BSA-beads). ELISAs for IL-1β and TNF-α were employed to quantitate cytokine levels in blood plasma without performing arduous and time-consuming extraction procedures. Over the course of a 6 hr incubation, LPS elicited a dose-dependent increase in TNF-α and IL-1β production. Preincubation of whole blood with interferon-γ prior to the addition of a suboptimal dose of LPS or BSA-beads resulted in a synergistic potentiation of IL-1β/TNF-α production. Dexamethasone, utilized in the treatment of rheumatoid arthritis, proved to be a potent inhibitor of cytokine biosynthesis in whole bloodex vivo. The measurement of cytokine biosynthesis in a relevant physiologic environment not only avoids non-specific monocyte activation, but also may increase our ability to predict clinical outcomes in rheumatoid arthritis and/or other inflammatory diseases.