gms | German Medical Science

Objective: Aim of the project was to develop an in vitro method for point of care measurement of the IL-23/Th-17-axis in peripheral blood immune cells in a whole blood assay. Innate stimuli were used to activate antigen-presenting monocytes, which in turn trigger Th17 differentiation. Long-term goal is the identification of prognostic parameters for the therapeutic response to biologicals.

Methods: Vacutainer vials were coated with immobilized TNF receptor 2 as mTNF stimulus or with IgG Fc fragments as controls. In a second set test of test tubes, ionized calcium and LPS were used. Whole blood was given directly into the tube to allow for stimulation of monocytes and lymphocyte in direct cell-cell contact. As read-out parameters, both monocytic and lymphocytic cytokines were determined by ELISA and by LUMINEX multiplex assay in the super at at after 16 h of incubation.

Results: In the project, priming and stimulation of peripheral blood monocytes in whole blood was optimized in order to maximize T cell activation during direct monocytes – T cell contact. With the final protocol, robust production of both monocytic and lymphocytic cytokines could be induced in whole blood samples from healthy donors. The combined stimulation with increased ionized calcium concentrations, and LPS was found to induce both the highest monocytic cytokines response and the strongest activation of IL-23 and IL-17.

Conclusion: The responsiveness of the IL-23/Th17 axis in peripheral blood samples can be monitored by an easy to use in-tube test assay followed by cytokine measurement in the supernatant. The system will be used in future diagnostic studies investigating a possible link between the IL-23/Th17 axis and clinical response to IL-17 – blocking therapies.