Blebs and apoptotic bodies are B cell autoantigens.

Mounting evidence suggests that systemic lupus erythematosus autoantigens are derived from apoptotic cells. To characterize the potential interactions between apoptotic cells and B cells, the D56R/S76R variant of 3H9, a murine autoantibody that binds to DNA, chromatin, and anionic phospholipids, was compared with DNA4/1, a human anti-DNA autoantibody. Flow cytometry revealed that only D56R/S76R bound to Jurkat cells treated with either of three distinct proapoptotic stimuli, Ab binding was dependent on caspase activity, and immunoreactivity developed subsequent to annexin V binding.

Structural basis for autoantibody recognition of phosphatidylserine-beta 2 glycoprotein I and apoptotic cells.

Apoptotic cells contain nuclear autoantigens that may initiate a systemic autoimmune response. To explore the mechanism of antibody binding to apoptotic cells, 3H9, a murine autoantibody with dual specificity for phospholipids and DNA, was used. H chain mutants of 3H9 were constructed, expressed as single-chain Fv (scFv) in Escherichia coli, and assessed for binding to phosphatidylserine, an antigen expressed on apoptotic cells.

Tandem affinity tags for the purification of bivalent anti-DNA single-chain Fv expressed in Escherichia coli.

Antibodies to DNA define an important autospecificity that arises in systemic lupus erythematosus (SLE). To elucidate the molecular features that may explain the pathogenesis of SLE, a heterologous system for expression of cloned V genes is often desirable. Here, a single-chain Fv coding domain was constructed by using the heavy- and light-chain V genes of a high-affinity site-directed mutant of the murine anti-dsDNA autoantibody, 3H9.

Initiation of systemic autoimmunity and sequence specific anti-DNA autoantibodies.

Antibodies to double-stranded DNA (dsDNA) are a defining feature of Systemic Lupus Erythematosus (SLE). The molecular characterization of anti-dsDNA autoantibodies reveals that they are actively selected for binding to antigen. Evidence for antigen selection includes the use of suitable rearrangement products, the switching of IgM isotype to IgG, and the acquisition of somatic mutations that raise the affinity for dsDNA.