ABSTRACT
Objective To investigate the effect of high mobility group box-1 protein (HMGB1) on inter-leukin-2 (1L-2) and interleukin-2 receptor α (IL-2α) expressions in human T lymphocytes and its potential regulat-ing mechanism in vitro. Method Human T lymphocytes were isolated and suspended, the cells were cultured with 20 μg/mL phytohemagglutinin (PHA) in 5% CO_2 at 37 ℃, recombinant human HMGB1 (rhHMGB1, 0, 10, 100, 1000 ng/mL) was added with the PHA and cultures were centrifuged at 12 and 48 hours for cell collect-ing. Reverse transcription polymerase chain reaction (RT-PCR) amplification was perfomed to determine gene ex-pressions of IL-2, IL-2Rα. IL-2, sIL-2R protein levels in cell culture supematants were measured by ELIZA. Re-sults After coincubated with rhHMGB1 (10, 100, and 1000 ng/mL) for 12 hours, IL-2 levels in cell culture su-pernatants respectively were 0 . 064 ± 0. 017 μg/L, 0.076±0.033 μg/L, and 0.061 ±0.02 μg/L, which were significantly higher compared with the untreated cells (0.045±0.011 μg/L, P < 0.05 or P < 0.01). Mean-while, IL-2 mRNA expression was markedly up-regulated following rhHMGB1 stimulation in various doses (F = 4.6872, P < 0.01). At 48 bourn, however, both IL-2 mRNA expression and protein production tended to de-crease along with an increased dose of dd-IMGB1 stimulationn. IL-2/sIL-2R ratio in 1000 ng/mL rhHMGB1 was markedly lower than that in 10 ng/ml rhHMGB1 (0.036±0.015 vs.0.055±0.017, P <0.05), together with down-regulation of IL-2Rα mRNA expression(P <0.01). Conclusions These data indieated that HMGBI could marked influence the IL-2/IL-2R expression in human T lymphocytes. With the increase in stimulating doses and prolongation of time, HMGBI might down-regulate T cell-mediated immune response of human lymphocytes.
ABSTRACT
Objective This study was performed to investigate the effect of high mobility group box-1 protein (HMGB 1) on immune function of human T lymphocytes in vitro and explore its potential role in cell-mediated immune dysfunction.Methods Fresh blood was obtained from healthy adult volunteers and peripheral blood mononuclear cells (PBMCs) were isolated,then rhHMGB 1 was added to PBMCs.Four-color flow cytometric (FCM) analysis was used for the measurement of intracellular cytokine including interleukin Results (1) Different stimulating time and dosage of rhHMGB 1 did not alter the number of IFN-a positive cells (Th 1).rhHMGB 1 stimulation provoked a dose-dependent and time-dependent increase in Th2 subset and decrease in ratio of Th 1 to Th2.(2) Compared with the untreated cells,when the cells were coincubated with rhHMGB 1 (10-100ng/ml) for 12 hrs,protein release of IL-2 and sIL-2R were significantly up-regulated.At 48 hrs,in contrast,protein production was relatively lower in cells after exposure to 100-1000 ng/ml rhHMGBI.Conclusions These findings demonstrated that HMGB1 has a dual influence on immune functions of human T lymphocytes.