Attenuation of αL and α4 expression on human activated CD4+ T cells with PDE8A inhibition

Background: The importance of a normal functioning immune system is crucial for
maintaining good health. When the immune system is impaired diseases may develop. Autoimmune diseases can be caused by aggressive adhesion and migration of T cells into the tissue resulting in inflamed endothelium, which further attracts entry of more cells, ending with a vicious cycle of endless inflammation and worsening condition with time.
Objectives: To reclaim CD4+ T cells for CD3+CD28+ T cell activation to mimic an activated adaptive immune system. By modelling an adaptive immune system and include drugs that interfere with the integrins that result in cellular adhesion to the endothelium, possibilities are in attenuation of cell adhesion.
Methods: Whole blood was drawn from volunteers. Peripheral blood mononuclear cells (PMBCs) were isolated with density gradient centrifugation. CD4+ T cell was isolated by CD4+ negative selection. Activation was initiated with stimulating Dynabeads. Activated T cells were dosed with PDE8 inhibitor to attenuate activation.
Results: Viability of PMBC isolation was 100%, of which 73.24% were lymphocytes and 26.23% of these were T cells. CD4+ T cell isolation retained 98.40% viability, with 95.27% lymphocytes of which 95.51% were T cells. 93.90% of these were CD4+ T cells. Activation was not successful.
Conclusion: We managed to isolate CD4+ cells in enough amounts from PMBCs to complete bead-stimulation. We showed that this is a reproducible method. We were not able to show the reliability when identifying the effect of PF-04957325 on the expression of the α4 and aL integrins. Instead, we observed a survival mechanism in action, which the PDE8A inhibition induced.