title: Following immunization antigen becomes concentrated in a limited number of APCs including B cells.
abstract: Immunization with the hen egg-white lysozyme (HEL) protein induces T cells to various of its peptide determinants. The distribution of such T cells, however, does not correlate with the peptide level of each epitope on class II molecules. For this reason, we sought information on the cells responsible for Ag presentation following immunization, hoping to understand the lack of immunodominance in this system. By tracking HEL, and the ensuing peptide/MHC complexes, we find the following: 1) that HEL in the draining lymph node gets concentrated in a limited number of APC, particularly in dendritic cells and macrophages, 2) that these APC are functionally capable of presenting both major and minor determinants of HEL over a 100-fold range of Ag dose, and 3) that B cells present Ag gained at early times after immunization, but only following higher dose immunization. These data indicate that the breadth of a response is maintained over a wide dosage range by concentration of Ag in a limited number of cells presenting high levels and a great diversity of epitopes.
authors.affiliation: Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO 63110, USA.
authors.forename: Craig A
authors.initials: CA
authors.lastname: Byersdorfer
authors.forename: Richard J
authors.initials: RJ
authors.lastname: Dipaolo
authors.forename: Shirley J
authors.initials: SJ
authors.lastname: Petzold
authors.forename: Emil R
authors.initials: ER
authors.lastname: Unanue
mesh_terms: D000818:Animals; D017951:Antigen Presentation; D000938:Antigen-Presenting Cells / Q000276:immunology* / Q000378:metabolism* / Q000473:pathology; D000941:Antigens / Q000008:administration & dosage* / Q000276:immunology* / Q000378:metabolism; D016175:B-Lymphocyte Subsets / Q000276:immunology* / Q000378:metabolism* / Q000473:pathology; D018984:Epitopes, T-Lymphocyte / Q000276:immunology / Q000378:metabolism; D000949:Histocompatibility Antigens Class II / Q000378:metabolism; D007114:Immunization; D016056:Immunodominant Epitopes / Q000276:immunology / Q000378:metabolism; D007279:Injections, Subcutaneous; D007457:Iodine Radioisotopes / Q000378:metabolism; D018655:Lymphocyte Count; D008231:Lymphopenia / Q000235:genetics / Q000276:immunology; D051379:Mice; D008810:Mice, Inbred C57BL; D008817:Mice, Mutant Strains; D009113:Muramidase / Q000008:administration & dosage* / Q000276:immunology* / Q000378:metabolism; D016176:T-Lymphocyte Subsets / Q000166:cytology / Q000276:immunology / Q000378:metabolism
chemical_list: D000941:Antigens; D018984:Epitopes, T-Lymphocyte; D000949:Histocompatibility Antigens Class II; C111388:I-Ak antigen; D016056:Immunodominant Epitopes; D007457:Iodine Radioisotopes; C421864:hen egg lysozyme; D009113:Muramidase