Figure 4. IL-2 accumulation decreases in response to viable P. gingivalis and its derived supernatant.

A- Jurkat T-cells (10⁶ cells/ml) were pre-treated with 10⁸ CFU/ml of viable or heat-killed (HK) P. gingivalis (MOI:100) as well as 10% untreated- or heat-treated (HT) supernatant from P. gingivalis broth cultures for 1 h. The cells were then stimulated with 50 ng/ml PMA and 1 µg/ml Calcium ionophore for 24 h. IL-2 accumulation was significantly reduced by viable, but not heat-killed P. gingivalis in Jurkat T-cells, while both untreated and heat-treated bacterial supernatant resulted in a significant IL-2 reduction. B- T-cells were pre-treated with the indicated concentrations of viable P. gingivalis (MOI:0.5, 1, 5, 10, 50 and 100, respectively) for 1 h followed by stimulation with 50 ng/ml PMA and 1 µg/ml Calcium ionophore for 24 h. IL-2 accumulation was reduced in a dose-dependent manner. C- Primary cells were isolated as described in materials and methods. Cells were pre-treated with viable or heat-killed P. gingivalis for 1 h, followed by stimulation with 50 ng/ml PMA and 1 µg/ml Calcium ionophore for 24 h. Viable, but not heat-killed P. gingivalis (MOI:100) resulted in a significant reduction in IL-2 accumulation. *-p<0.05; **-p<0.01; ***-p<0.001 (Statistical significance between different treatments and the positive control PMA/Iono, Student's t-test).