Neuropsychiatric SLE: from animal model to human.

Animal models are a key element in disease research and treatment. In the field of neuropsychiatric lupus research, inbred, transgenic and disease-induced mice provide an opportunity to study the pathogenic routes of this multifactorial illness. In addition to achieving a better understanding of the immune mechanisms underlying the disease onset, supplementary metabolic and endocrine influences have been discovered and investigated. The ever-expanding knowledge about the pathologic events that occur at disease inception enables us to explore new drugs and therapeutic approaches further and to test them using the same animal models. Discovery of the molecular targets that constitute the pathogenic basis of the disease along with scientific advancements allow us to target these molecules with monoclonal antibodies and other specific approaches directly. This novel therapy, termed "targeted biological medication" is a promising endeavor towards producing drugs that are more effective and less toxic. Further work to discover additional molecular targets in lupus' pathogenic mechanism and to produce drugs that neutralize their activity is needed to provide patients with safe and efficient methods of controlling and treating the disease.

Cross-reactivity between annexin A2 and Beta-2-glycoprotein I in animal models of antiphospholipid syndrome.

Antiphospholipid syndrome (APS) affects coagulation and the brain by autoimmune mechanisms. The major antigen in APS is beta-2-glycoprotein I (ß2-GPI) is known to complex with annexin A2 (ANXA2), and antibodies to ANXA2 have been described in APS. We measured these antibodies in mice with experimental APS (eAPS) induced by immunization with ß2-GPI. Sera of these mice reacted significantly with recombinant ANXA2 by enzyme-linked immunosorbent assay (ELISA) and the eAPS mice had significantly high levels of immunoglobulin G (IgG) in the brain by immunoblot assays compared to adjuvant immunized controls. Immunoprecipitation performed by mixing eAPS brain tissue with protein-G beads resulted in identification of two autoantigens unique to the eAPS group, one of which was ANXA2. In order to study more directly and methodically the specific role of anti-ANXA2 antibodies in APS, we immunized mice with ß2-GPI which contained no ANXA2 or with ANXA2 and measured antibodies to these proteins. Levels of antibodies to ANXA2 measured by ELISA were 0.72 ± 0.007 arbitrary units (a.u), 0.24 ± 0.03 and 0.02 ± 0.01 a.u for sera from ANXA2, ß2-GPI and control mice, respectively (p < 0.0001 and p = 0.037 for the comparison of the ANXA2 and ß2-GPI groups to the controls). Purified IgG from ß2-GPI sera did not show cross-binding with ANXA2. Antibodies to ß2-GPI and phospholipids were found in the ß2-GPI immunized group only. The present study suggests an immune response to the ß2-GPI-ANXA2 complex in eAPS and provides a novel ANXA2 immunization model which will serve to study the role of ANXA2 antibodies in of APS.