title: Characterization of (4-hydroxy-3-nitrophenyl)acetyl (NP)-specific germinal center B cells and antigen-binding B220- cells after primary NP challenge in mice.
abstract: Previous studies examining the primary germinal center (GC) response to SRBC in mice demonstrated a steady ratio of IgM(+) to isotype-switched GC B cells and a persistent population of GC B cells with a founder phenotype. These characteristics held true at the inductive, plateau, and dissociative phases of the GC response, suggesting a steady-state environment. To test whether these characteristics apply to the primary response of other T cell-dependent Ags, the present study examined the GC response after challenge with (4-hydroxy-3-nitrophenyl)acetyl (NP) in C57BL/6 mice. Multiparameter flow cytometric analysis was used to assess the phenotype of splenic NP-reactive cells at multiple time points after immunization. Results of these studies demonstrated the characteristics of the SRBC-induced GC reaction to be fully maintained in the NP response. In particular, there was a steady ratio of nonswitched to switched B cells, with the majority of NP-reactive GC B cells displaying IgM. In addition, a substantial frequency of B220(-) NP-binding cells was observed in the spleen at later time points after NP challenge. Although these cells were IgE(+), they were found to express both kappa and lambda L chains and display the high-affinity IgE Fc (FcepsilonRI) receptor, suggesting that this population is not of B cell origin. Adoptive transfer studies further demonstrated the B220(-) NP-binding subset to be derived from the myeloid lineage.
authors.affiliation: Department of Pathology, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA.
authors.forename: Kristy L
authors.initials: KL
authors.lastname: Wolniak
authors.forename: Randolph J
authors.initials: RJ
authors.lastname: Noelle
authors.forename: Thomas J
authors.initials: TJ
authors.lastname: Waldschmidt
mesh_terms: D000818:Animals; D016175:B-Lymphocyte Subsets / Q000276:immunology* / Q000378:metabolism; D018985:Epitopes, B-Lymphocyte / Q000008:administration & dosage / Q000276:immunology*; D005260:Female; D018858:Germinal Center / Q000166:cytology / Q000276:immunology* / Q000378:metabolism; D006241:Haptens / Q000008:administration & dosage / Q000276:immunology*; D017493:Leukocyte Common Antigens / Q000378:metabolism*; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D009596:Nitrophenols / Q000008:administration & dosage* / Q000276:immunology*; D010648:Phenylacetates; D011485:Protein Binding / Q000276:immunology
chemical_list: D018985:Epitopes, B-Lymphocyte; D006241:Haptens; D009596:Nitrophenols; D010648:Phenylacetates; C026242:4-hydroxy-5-nitrophenyl acetic acid; D017493:Leukocyte Common Antigens