title: Effects of in vivo monoclonal anti-I-A antibody treatment in neonatal mice on intrathymic and peripheral class II antigen expression.
abstract: Intrathymic, Ia-bearing antigen-presenting cells (APC) are believed to play an important role in the development of a mature, functional T-cell repertoire. We used chronic in vivo treatment of neonatal mice with anti-I-A monoclonal Ab (MAb) to examine the expression of I-A and I-E antigens on intrathymic and peripheral APC. Three weeks after continuous treatment with anti-I-A MAb, FACS analysis of unfractionated spleen cells revealed a 75-90% reduction in the number of I-A bearing cells. Splenic antigen-presenting capacity measured by the ability of unseparated or density gradient-enriched APC to stimulate I-A- or I-E-reactive T-cell hybridomas was also greatly reduced. In contrast to the expression of I-A and I-E molecules in the splenic APC, anti-I-A MAb treatment resulted in decreased thymic APC I-A expression without significant changes in I-E as measured by FACS analysis. This was confirmed in functional studies in which allo-I-A- or auto-I-A-reactive T-cell hybridomas could not be stimulated by treated thymic APC. Unlike splenic APC, anti-I-A-treated thymic APC did not differ significantly from normals in their ability to stimulate allo-I-E-reactive T hybridomas. This lack of linkage or comodulation of I-A and I-E expression on thymic but not splenic APC may allow us to study the role of I-A molecules and I-E molecules on the development and expansion of functional, mature T-cell repertoires.
authors.affiliation: Department of Pathology, Harvard Medical School, Boston, Massachusetts 02115.
authors.forename: W W
authors.initials: WW
authors.lastname: Williams
authors.forename: L D
authors.initials: LD
authors.lastname: Falo
authors.forename: C Y
authors.initials: CY
authors.lastname: Lu
authors.forename: B
authors.initials: B
authors.lastname: Benacerraf
authors.forename: M S
authors.initials: MS
authors.lastname: Sy
mesh_terms: D000818:Animals; D000831:Animals, Newborn / Q000276:immunology*; D000911:Antibodies, Monoclonal; D000938:Antigen-Presenting Cells / Q000276:immunology*; D000949:Histocompatibility Antigens Class II / Q000276:immunology*; D008213:Lymphocyte Activation; D008211:Lymphocyte Cooperation; D051379:Mice; D013154:Spleen / Q000166:cytology / Q000276:immunology; D013601:T-Lymphocytes / Q000276:immunology*; D006377:T-Lymphocytes, Helper-Inducer / Q000276:immunology; D013950:Thymus Gland / Q000276:immunology*
chemical_list: D000911:Antibodies, Monoclonal; D000949:Histocompatibility Antigens Class II; C024138:I-E-antigen