The role of IFN-γ and toll-like receptors in nephropathy induced by Toxoplasma gondii infection

The pathologic links between Toxoplasma gondii infections and renal diseases have not yet been established. Gamma interferon (IFN-gamma) and Toll-like receptors (TLRs) are involved in the host defense mechanism against T gondii infection. The role of IFN-gamma and TLRs in renal function of T gondii-infected mice was studied using wild type (WT), TLR2-deficient and TLR4-deficient mice perorally infected with cysts of an avirulent cyst-forming Fukaya strain of T gondii. T gondii was abundant in kidneys in IFN-gamma KO (GKO) mice as determined by a quantitative competitive-polymerase chain reaction (QC-PCR). But, T gondii was not detected in kidneys in WT, TLR2-deficient and TLR4-deficient mice. Interestingly, renal function of TLR2-deficient and TLR4-deficient mice was damaged as evaluated by serum creatinine, serum blood urea nitrogen (BUN), and urine albumin/creatinine ratio (ACR), whereas renal function of GKO and WT mice was not damaged. Histopathology of TLR2-deficient mice exhibited glomerular and extracellular matrix swelling with advancing glomerular tissue proliferation, thickened Bowman's capsules and vacuolization of tubules. Renal immunofluorescence study of T gondii-infected TLR2-deficient mice displayed positive staining of the glomerular basement membrane, mesangial areas and peritubular capillaries. The damage of kidney from TLR4-deficient mice was less severe compared to TLR2-deficient mice, and histopathological damage of kidney was not observed in WT and GKO mice. These results indicate that TLR2, but not IFN-gamma, plays a role in the protection of the renal function against T gondii infection.