Different effect of Toxoplasma gondii infection on adhesion capacity of fibroblasts and monocytes

This study investigated the effect of infection with the apicomplexan parasite Toxoplasma gondii, in combination with the concomitant cytokine environment (IFN-gamma/TNF-alpha), on adhesion of THP-1 monocytic cells to MRC-5 fibroblasts. Surprisingly, infection of THP-1 cells decreased their adhesion to the MRC-5 cell monolayer. This decrease was compensated by IFN-gamma/TNF-alpha stimulation. In contrast, infection of MRC-5 cells significantly increased adhesion, which was synergistically augmented by cytokine stimulation. Levels of ICAM-1 (CD54) on MRC-5 cells, as well as LFA-1 (CD11a) on THP-1 cells, were not changed by infection, neither in resting, nor in cytokine stimulated cells. These results show that T. gondii infection alters adhesion properties and reactivity to cytokine stimulation in a cell-specific way.