PRODUCTION OF CROSS-REACTIVE AUTOANTIBODY BINDING TO BOVINE SERUM ALBUMIN IN THE D-GALACTOSE-INDUCED AGING MOUSE MODEL

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 D-gal 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.