Amelioration of experimental systemic lupus erythematosus (SLE) by retrovirus infection

Experimental SLE can be induced in susceptible 129/J mice by immunization with a human anti-DNA antibody bearing a common idiotype designated 16/6 Id. Immunized mice develop autoantibodies, leukopenia, proteinuria, and immune complex deposits in renal glomeruli. Case reports have described clinical improvement in SLE in individuals becoming infected with HIV-1. Because 129/J mice are susceptible to experimental SLE and to infection with the BM5def murine leukemia virus (MuLV) mixture but do not develop the lymphoproliferative/ immunodeficiency disorder known as murine AIDS (MAIDS), we superimposed this infection on immunization with the 16/6 Id. Multiple effects were observed. First, we noted an amelioration in the course of experimental SLE. Second, both in experimental SLE and in BM5def MuLV infection, immunoreactivity to HIV-1 gp120 was demonstrated, although gp120 is not present in the BM5def MuLV viruses. Third, production of autoantibodies characteristically found in SLE, e.g., anti-DNA, anti-RNP, and anti-SSA, was seen in BM5def MuLV-infected mice, demonstrating that an immune response as a consequence of infection had occurred despite the absence of MAIDS induction. We conclude that (1) retrovirus inoculation may ameliorate the course of experimental SLE; and (2) retrovirus inoculation, even in the absence of MAIDS induction, induces an immunologic response which promotes the production of potentially pathogenic autoantibodies.