B-cell repertoire specific for an unfolded self-determinant of mouse lysozyme escape tolerance and dominantly participate in the autoantibody response.
We previously found that autoantibodies against mouse lysozyme (ML) were strongly induced in normal BALB/c mice when immunized with mutant ML that has triple mutations rendering the dominant T-cell epitope of hen egg lysozyme (HEL), HEL 107-116. As T cells specific for HEL 107-116 were primed in these mice, the anti-ML immunoglobulin G (IgG) responses would be the result of collaborations between autoreactive B cells specific for ML and T cells specific for HEL 107-116. Serum IgG responses against ML were dominantly focused on the ML 14-69 region, indicating that B cells responding to the epitope escape tolerance. In the present study, we prepared several monoclonal antibodies (mAbs) specific for ML 14-69 and examined their antigen specificities in detail, to characterize the nature of the remaining B-cell repertoire specific for ML. mAbs specific for ML 14-69 interacted weakly with soluble, native ML, but the interactions were strengthened by denaturation of ML. The apparent affinity constants between these mAbs and ML showed an increase, ranging from six- to 80-fold, by denaturation of ML. Therefore, these mAbs were more specific for the denatured determinant than for the determinant in the native structure. These results indicate that a substantial number of autoreactive B cells, specific for the unfolded conformation of ML, escape tolerance and are dominantly involved in the autoantibody response to ML. Our finding provides important information to understand the naturally occurring autoreactive B-cell repertoire in normal mice.
Tsujihata
Yoshiyuki
Y
Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka, Japan.
Mizukami
Yousuke
Y
Ueda
Tadashi
T
So
Takanori
T
Imoto
Taiji
T
D000595:Amino Acid Sequence; D000818:Animals; D000911:Antibodies, Monoclonal; D000915:Antibody Affinity / Q000276:immunology; D000918:Antibody Specificity / Q000276:immunology; D001323:Autoantibodies / Q000276:immunology*; D001402:B-Lymphocytes / Q000276:immunology*; D000939:Epitopes / Q000276:immunology; D005260:Female; D007108:Immune Tolerance / Q000276:immunology; D007074:Immunoglobulin G / Q000276:immunology; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D008954:Models, Biological; D009113:Muramidase / Q000276:immunology*
D000911:Antibodies, Monoclonal; D001323:Autoantibodies; D000939:Epitopes; D007074:Immunoglobulin G; D009113:Muramidase