Homocysteine-induced endoplasmic reticulum protein (Herp) was discovered as a potential mimic antigen for eliciting anti-DNA antibodies in patients with lupus nephritis by screening cDNA libraries from peripheral lymphocytes of patients with active lupus nephritis. Herp is located within the endoplasmic reticulum (ER) membrane in various cell types and its production is up-regulated by stress such as viral infection, hypoxia, or Ca2+ imbalance. Chondrex, Inc. provides a mouse monoclonal antibody, Clone HT2, for detecting Herp by western blot or ELISA.
|Product||Cross-Reactivity||Subtype||Quantity||Application||Catalog #||Price (USD)|
|Anti-Human Herp Antibody, Clone HT2||H||Mouse IgG1||1 mg/ml x 0.1 ml||ELISA
|Anti-Human Herp Antibody, Clone HT2, Biotinylated||H||Mouse IgG1||1 mg/ml x 0.1 ml||ELISA
Background Information about Herp
Anti-DNA antibodies play a key role in the pathogenesis of lupus nephritis in systemic lupus erythematosus (SLE). However, the mechanism of anti-DNA antibody production remains unknown. Since the immunogenicity of native DNA is poor, it has been assumed that DNA mimicry substances sharing a similar conformation with native DNA might elicit antibodies that cross-react with native DNA. By screening cDNA libraries of peripheral lymphocytes from patients with active lupus nephritis, Herp was discovered as a potential mimic antigen that might elicit anti-DNA antibodies in patients who suffer from cell stress.
Importantly, Balb/c mice immunized with recombinant human Herp produced anti-nuclear and anti-DNA antibodies, which react not only with single stranded DNA (ssDNA), but also react with double stranded DNA (dsDNA) by ELISA (Table 1). Furthermore, IgG deposition along renal glomeruli, which is a typical pathological feature in lupus nephritis, was observed in these mice. These results indicate that Herp mimics the structure of dsDNA, and is capable of eliciting anti-DNA antibodies in mice.
Furthermore, it was found that anti-DNA antibodies in patients with lupus nephritis cross-react with Herp by ELISA using affinity purified anti-DNA antibodies from sera of patients with active lupus nephritis (Table 2). IgG fraction from normal controls also bound to Herp, but not with dsDNA by ELISA, indicating that at least two antigenic epitopes are present on the Herp molecule, one pathogenic and the other non-pathogenic due to the mimicry of DNA.