T-cell function
For each of the 4 conditions (control, LPS, IFN-γ, LPS plus IFN-γ), the level of T-cell activation in both CD4 and CD8 lymphocytes was measured (Fig. 4). In CD4 T-cells, the level of intracellular IFN-γ production increased in stimulated blood in control conditions, as compared with unstimulated blood (p = <0.001). However, the addition of 100 ng/ml LPS led to decreased CD4 activation (p = 0.029). IFN-γ treatment alone did not influence CD4 activation compared with control conditions. No differences were seen in CD4 T-cells with a combination of LPS and IFN-γ treatment, compared with LPS treatment alone.
In CD8 T-cells, a large increase in T-cell activation was seen in stimulated control cells compared with unstimulated conditions. Again, 100 ng/mL LPS decreased T-cell activation with the percentage of IFN-γ-producing CD8 T-cells declining from 15.67 (± 4.05)% to 9.25 (±4.06)% (p = 0.004). The addition of IFN-γ alone did not lead to any change in CD8 T-cell activation as compared to the control condition. The addition of both IFN-γ and LPS conditions did not further affect the level of CD8 T-cell activation. This was comparable to the 9.25 (±4.05)% of activated CD8 T-cells seen with LPS alone.