[The effect of interleukin-12 on the production of Th(1) and Th(2) cytokines by peripheral blood mononuclear cells from patients with tuberculosis].

OBJECTIVE

To investigate the effect of IL-12 on the production of IFN-gamma and IL-4 by peripheral blood mononuclear cells (PBMC) from patients with tuberculosis.

METHODS

PBMCs were isolated and cultured with RPMI 1640, PPD, PPD + rhIL-12, PPD + anti-IL-12, respectively. The level of IFN-gamma and IL-4 was detected with ELISA.

RESULTS

Compared with the PPD group, IL-12 increased the production of IFN-gamma (321.6 +/- 87.7 vs 452.5 +/- 111.4, 387.0 +/- 70.8 vs 515.4 +/- 44.1, respectively), but decreased the production of IL-4 (54.6 +/- 11.0 vs 41.3 +/- 13.5, 55.1 +/- 9.5 vs 38.2 +/- 12.9, respectively) in the patients and the healthy individuals; anti-IL-12 blocked this effect. The level of IFN-gamma was lower in tuberculosis patients than that in the healthy controls. The IL-4 level was not different between the two groups (P > 0.05). The levels of IFN-gamma and IL-4 were lower in recurrent tuberculosis than those in the newly-diagnosed cases (P < 0.05).

CONCLUSIONS

IL-12 induced IFN-gamma production and inhabited IL-4 expression, modulating the balance between TH(1) and TH(2) cytokines, suggesting that IL-12 enhances the host defense against tuberculous infection. IL-12 may be used for treatment of tuberculosis and vaccine development.