Bispecific Abs against modified protein and DNA with oxidized lipids

Abstract

4-Hydroxy-2-nonenal (HNE), a racemic mixture of 4R-and 4S-enantiomers, is a major product of lipid peroxidation and is believed to be largely responsible for the cytopathological effects observed during oxidative stress. HNE reacts with histidine to form a stable HNE-histidine Michael addition-type adduct possessing three chiral centers in the cyclic hemiacetal structure. We have previously raised the mAbs, anti-R mAb 310 and anti-S mAb S412, that enantioselectively recognized the R-HNE-histidine and R-HNEhistidine adducts, respectively, and demonstrated the presence of both epitopes in vivo. In the present study, to further investigate the anti-HNE immune response, we analyzed the variable genes and primary structure of these Abs and found that the sequence of R310 was highly homologous to anti-DNA autoantibodies, the hallmark of systemic lupus erythematosus. An x-ray crystallographic analysis of the R310 Fab fragment showed that the R-HNEhistidine adduct binds to a hydrophobic pocket in the antigenbinding site. Despite the structural identity to the anti-DNA autoantibodies, however, R310 showed only a slight crossreactivity with the native double-stranded DNA, whereas the Ab immunoreactivity was dramatically enhanced by the treatment of the DNA with 4-oxo-2-nonenal (ONE), an analog of HNE. Moreover, the 7-(2-oxo-heptyl)-substituted 1,N 2 -etheno-type ONE-2 -deoxynucleoside adducts were identified as alternative epitopes of R310. Molecular mimicry between the R-HNE-histidine configurational isomers and the ONE-DNA base adducts is proposed for the dual crossreactivity.4-hydroxy-2-nonenal ͉ anti-DNA autoantibody ͉ lipid peroxidation ͉ oxidative stress ͉ systemic lupus erythematosus I t is estimated that most of the proteins in the human body are posttranslationally modified. Such modifications include phosphorylation, methylation, and glucosylation. They are enzymemediated and homeostatically important, either to carry out a particular structural or functional role or to allow the efficient recycling of the amino acid constituents. However, several lines of evidence indicate that the nonenzymatic oxidative modification of proteins and the subsequent accumulation of the modified proteins have been found in cells during aging and oxidative stress and in various pathological states, including premature diseases, muscular dystrophy, rheumatoid arthritis, and atherosclerosis (1). The important agents that give rise to the modification of proteins are represented by oxidized lipid metabolites, such as 2-alkenals, 4-hydroxy-2-alkenals, and ketoaldehydes (2, 3). These metabolites are considered important mediators of cell damage because of their ability to covalently modify biomolecules, which can disrupt important cellular functions and can cause mutations (2).4-Hydroxy-2-nonenal (HNE), a racemic mixture of 4R-and 4S-enantiomers, is a major product of lipid peroxidation and is believed to be largely responsible for the cytopathological effects observed during oxidative stress (2). HNE exerts these effects because of its...

Elevated oxidative stress in erythrocytes due to a SOD1 deficiency causes anaemia and triggers autoantibody production

“…An anion exchanger (band 3) is a predominant autoantigen in erythrocyte membranes [39,40] and may correspond to the positive band observed at a high molecular mass in Figure 5(B). In addition, a lipid peroxidation product, 4-hydroxynonenal, and/or its protein adduct may be an antigen in oxidized erythrocytes [41].…”

Oxidative Stress–induced Antibodies to Carbonyl-modified Protein Correlate with Severity of Chronic Obstructive Pulmonary Disease

“…Another key feature of many autoimmune diseases is the presence of antinuclear antibodies. It is interesting to note, therefore, that antibodies against adducts of 4HNE, a carbonyl known to be elevated in COPD (13), have dual specificity against both DNA and 4HNE-modified protein leading to an antinuclear antibody-type response (39).…”

Antibodies against 4-Hydroxy-2-nonenal Modified Epitopes Recognized Chromatin and Its Oxidized Forms: Role of Chromatin, Oxidized Forms of Chromatin and 4-Hydroxy-2-nonenal Modified Epitopes in the Etiopathogenesis of SLE

“…HNE exerts these effects because of its facile reactivity with biological materials, including proteins [2]. It is reported that the sequence of an anti-HNE monoclonal antibodies (mAb) has highly homologous to the anti-DNA autoantibodies [3]. Excess generation of reactive oxygen species (ROS) have the ability, either directly or indirectly, to damage proteins, DNA, lipids and other cell biomolecules [4,5].…”