Production of Cross-Reactive Autoantibody Binding to Bovine Serum Albumin in the D-Galactose-Induced Aging Mouse Model

Abstract

The D-galactose (D-gal)-induced animal model, generated by repeated subcutaneous D-gal injections over approximately 6 weeks, has been frequently used for diabetes and aging research. However, little research has investigated the direct correlation between D-gal and autoantibody formation despite several reports on diabetes-and aging-related autoantibodies. The purpose of this study was to determine whether repetitive injection of D-gal can induce autoantibody production in mice. First, we used Bovine Serum Albumin (BSA) and Advanced Glycation End products (AGE)-BSA as the test antigens. The immunoreactivity of serum samples from mice treated with D-gal for 6 weeks was evaluated using Enzyme-Linked Immunosorbent Assay (ELISA). We found that serum samples of D-gal-treated mice had significantly high antibody titers against both BSA and AGE-BSA. Furthermore, the result showed that aminoguanidine treatment, an AGE inhibitor tended to decrease this immunoreactivity. The results of competitive inhibition ELISA using BSA and AGE-BSA as the competitors suggested that the serum samples from D-gal-treated mice contained antibodies not only against BSA but also specific to AGE-BSA. To assess whether the immunoreactivity against BSA is comparable to that against Mouse Serum Albumin (MSA), we examined the reactivity of D-gal-induced antibodies against MSA. Unexpectedly, D-gal-induced antibodies did not react with MSA. This suggests that the production of antibodies by Dgal is in response to an unknown antigen(s), aside from MSA, in mice and that this unknown antigen(s) may share similar sequences or three-dimensional structures with BSA.

Splenocyte proliferation and anaphylaxis induced by BSA challenge in a D-galactose-induced aging mouse model

“…In this regard, D-gal-treated mice were probably sensitised by some unknown endogenous protein(s) that share(s) an epitope with BSA. In previous studies, we confirmed that the IgG antibody cross-reacts with BSA [5, 6]. Many studies have shown that mouse anaphylaxis is mediated by IgE, which stimulates histamine and platelet activating factor (PAF), or by IgG, which stimulates PAF [10–12].…”

“…We recently reported on the formation of cross-reactive autoantibodies binding to BSA, but not MSA, in mice subcutaneously injected repeatedly with reducing sugars [5]. Additionally, we confirmed that the formation of this autoantibody is dependent on the route of administration (i.e., not oral or intraperitoneal but only subcutaneous) [6].…”

“…This animal model shows an accelerated aging phenotype that may be due to excessive formation of reactive oxygen species (ROS) and the accumulation of advanced glycation end products (AGEs) [2–4]. We previously found that the cross-reactive autoantibody generated in this D-gal-induced aging mouse model did not bind to mouse serum albumin (MSA), but did bind to bovine serum albumin (BSA) [5]. Additionally, we found that administration of other reducing sugars (glucose or fructose) by subcutaneous injection also led to the formation of an autoantibody that cross-reacted with BSA [6].…”

Experimental immunology The production of cross-reactive autoantibodies that bind to bovine serum albumin in mice administered reducing sugars by subcutaneous injection

“…Previously, we identified the formation of cross-reactive autoantibodies binding to bovine serum albumin (BSA) in the D-gal induced mouse model [14]. We considered whether the formation of autoantibody was D-gal specific.…”

“…The D-galactose (D-gal) induced animal model, which is established by the consecutive injection of D-gal for ∼6 weeks, has frequently been used to investigate the influence of excessive AGEs on the body [ 10 – 13 ]. Previously, we identified the formation of cross-reactive autoantibodies binding to bovine serum albumin (BSA) in the D-gal induced mouse model [ 14 ]. We considered whether the formation of autoantibody was D-gal specific.…”