Peptides based on the complementarity-determining regions of a pathogenic autoantibody mitigate lupus manifestations of (NZB × NZW)F1 mice via active suppression

Two peptides based on the complementarity-determining regions (CDR) 1 and 3 (pCDR1 and pCDR3) of a murine monoclonal anti-DNA autoantibody that expresses the common idiotype 16/6Id were shown to down-regulate systemic lupus erythematosus (SLE)-associated T cell responses and to prevent the development of clinical symptoms in the SLE-prone mice, (NZB 3 NZW)F1 .I n the present study the ability of the CDR-based peptides to treat an already established disease was tested. Mice were given 10 weekly injections of peptides either i.v. or s.c. The treatment led to a moderate reduction in the anti-DNA autoantibody titer, and a significant decrease in proteinuria and kidney pathology. The CDR-based peptides affected the pathogenic isotypes (IgG2a and IgG3) of the anti-DNA antibodies in the serum and in immune complexes in the kidneys. Both peptides mitigated disease manifestations and prolonged the survival of mice that were treated starting at the age of 7 months when full-blown disease was already developed. Furthermore, some beneficial effects of treatment with the CDR-based peptides could be adoptively transferred to diseased recipients. A reduction in the secretion of IL-2, IFN-g, IL-4 and IL-10 was detected in supernatants of splenocytes of the treated mice. In contrast, treatment up-regulated the immunosuppresive cytokine-transforming growth factor-b. Thus the ameliorating effect of the CDR-based peptides on SLE manifestations is at least partially via the immunomodulation of the cytokine profile.