The story of the 16/6 idiotype and systemic lupus erythematosus

Idiotypic analyses of anti-DNA autoantibodies were widely reported a decade ago. More than 100 studies were conducted on one of the main analyzed idiotypes, the 16/6 Id of the anti-ssDNA monoclonal antibody. In this review we summarize current knowledge on the characteristics of the 16/6 Id, its link to infection and its target epitopes on other molecules known so far. This includes the modulation of T and B cell responses and gene expression by the 16/6 mAb in vitro and in vivo. We focus on the ability and mechanisms by which this idiotype induces experimental lupus in naïve mice, manifested by autoantibody spread, kidney and brain involvement, and leukopenia associated with enhanced sedimentation rate. We also discuss various therapeutic modalities to treat 16/6 induced lupus in mice.