The induction of renal autoantigen-specific T cells by a local Listeria monocytogenes infection.

In order to examine the possibility that a local chronic infection can induce organ-specific autoimmune disease, we inoculated unilateral kidneys with viable Listeria monocytogenes (intrarenal infection). The delayed footpad reaction against syngeneic kidney homogenate (KH) became positive from 1 week after initiating the intrarenal infection. A proliferative response of the spleen T cells from the infected mice was also observed against KH from 1 week after initiating the intrarenal infection, but no such response was seen against liver homogenate (LH). In contrast, an intravenous Listeria infection did not induce a delayed footpad reaction or proliferative response against KH, suggesting that these autoimmune responses were not caused by molecular mimicry between renal antigens and Listeria antigens. Furthermore, the ability to transfer the autoimmune response of spleen T cells from intrarenally infected mice was examined. The transferred mice showed a positive delayed footpad reaction against KH and an interstitial infiltration of mononuclear cells in their kidneys. These results demonstrate that the intrarenal Listeria infection induced renal autoantigen-specific T cells, which subsequently induced an autoimmune interstitial nephritis (AIN). The autoreactive T cells were all induced without immunization by autoantigens mixed with complete Freund's adjuvant. Based on these findings, we propose that a local bacterial infection may induce an autoimmune response against autoantigens in the infected organ and subsequently trigger organ-specific autoimmune disease.