title: Mouse lysozyme-M knockout mice reveal how the self-determinant hierarchy shapes the T cell repertoire against this circulating self antigen in wild-type mice.
abstract: We have studied T cell tolerance to defined determinants within ML-M using wild-type (WT; ML-M(+/+)) and LysMcre (ML-M(-/-)) C3H (H-2(k)) mice to determine the relative contribution of ML-M-derived epitopes vs those from other self Ags in selection of the ML-M-specific T cell repertoire. ML-M was totally nonimmunogenic in WT mice, but was rendered immunogenic in LysMcre mice. Most of the response to ML-M in LysMcre mice was directed to the immunodominant determinant region 105-119. This determinant is spontaneously displayed (without adding exogenous ML-M) by macrophages of WT, but not LysMcre, mice and is stimulatory for peptide 105-119 (p105-119)-primed T cells. Moreover, neonatal tolerization of LysMcre mice with p105-119 or ML-M abrogated the T cell response to subsequent challenge with ML-M or p105-119. Furthermore, p95-109 and p110-125 of ML-M were immunogenic in LysMcre mice, but not in WT mice, thereby representing subdominant, tolerance-inducing epitopes of ML-M. As expected, the T cell repertoire to cryptic ML determinants in WT mice was also intact in LysMcre mice. Furthermore, the pattern of response to the related homologue of ML-M, hen eggwhite lysozyme, was similar in these two groups of mice. Thus, several codominant T cell determinants within ML-M contribute significantly to tolerance induction, and the anti-cryptic T cell repertoire to ML-M was positively selected on non-ML-M self ligands. These results reveal that the induction of self tolerance to a multideterminant protein follows the quantitative hierarchy of self-determinant expression and are of relevance in understanding the pathogenesis of autoimmunity.
authors.affiliation: Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, MD 21201, USA.
authors.forename: Pratima
authors.initials: P
authors.lastname: Sinha
authors.forename: Howard H
authors.initials: HH
authors.lastname: Chi
authors.forename: Hong R
authors.initials: HR
authors.lastname: Kim
authors.forename: Björn E
authors.initials: BE
authors.lastname: Clausen
authors.forename: Brian
authors.initials: B
authors.lastname: Pederson
authors.forename: Eli E
authors.initials: EE
authors.lastname: Sercarz
authors.forename: Irmgard
authors.initials: I
authors.lastname: Forster
authors.forename: Kamal D
authors.initials: KD
authors.lastname: Moudgil
mesh_terms: D000818:Animals; D017951:Antigen Presentation; D001324:Autoantigens / Q000737:chemistry / Q000235:genetics / Q000276:immunology*; D015551:Autoimmunity; D003433:Crosses, Genetic; D018984:Epitopes, T-Lymphocyte / Q000737:chemistry / Q000276:immunology*; D005838:Genotype; D007114:Immunization; D016056:Immunodominant Epitopes / Q000737:chemistry / Q000276:immunology; D008264:Macrophages / Q000276:immunology; D008297:Male; D051379:Mice; D008809:Mice, Inbred C3H; D018345:Mice, Knockout; D009113:Muramidase / Q000737:chemistry / Q000172:deficiency / Q000235:genetics / Q000276:immunology*; D010446:Peptide Fragments / Q000737:chemistry / Q000276:immunology; D010641:Phenotype; D017634:Self Tolerance / Q000276:immunology*; D016176:T-Lymphocyte Subsets / Q000276:immunology*
chemical_list: D001324:Autoantigens; D018984:Epitopes, T-Lymphocyte; D016056:Immunodominant Epitopes; D010446:Peptide Fragments; C421864:hen egg lysozyme; D009113:Muramidase; C472450:lysozyme M, mouse