title: T15-idiotype-negative B cells dominate the phosphocholine binding cells in the preimmune repertoire of T15i knockin mice.
abstract: T15i knockin (KI) mice express a H chain that is encoded by a rearranged T15 VDJ transgene which has been inserted into the J(H) region of chromosome 12. This T15H chain combines with a kappa22-33 L chain to produce a T15-Id+ Ab having specificity for phosphocholine (PC). Inasmuch as T15-Id+ Abs dominate the primary immune response to PC in normal mice, it was surprising to find that 80% of the PC-dextran-binding B cells in unimmunized homozygous T15i KI mice were T15-Id-. Analysis of L chains expressed in these T15-Id-, PC-specific B cells revealed that two L chains, kappa8-28 and kappa19-15, were expressed in this population. The V(kappa) region of these L chains was recombined to J(kappa)5, which is typical of L chains present in PC-specific Abs. When T15i KI mice were immunized with PC Ag, T15-Id+ B cells expanded 6-fold and differentiated into Ab-secreting cells. There was no indication that the T15-Id- B cells either proliferated or differentiated into Ab-secreting cells following immunization. Thus, T15-Id- B cells dominate the PC-binding population, but they fail to compete with T15-Id+ B cells during a functional immune response. Structural analysis of T15H:kappa8-28L and T15H:kappa19-15L Abs revealed L chain differences from the kappa22-33 L chain which could account for the lower affinity and/or avidity of these Abs for PC or PC carrier compared with the T15-Id+ T15H:kappa22-33L Ab.
authors.affiliation: Laboratory of Immunology, Gerontology Research Center, National Institute on Aging/NIH, 5600 Nathan Shock Drive, Baltimore, MD 21224, USA. hul@grc.nia.nih.gov
authors.forename: Lina
authors.initials: L
authors.lastname: Hu
authors.forename: Louis J
authors.initials: LJ
authors.lastname: Rezanka
authors.forename: Qing-Sheng
authors.initials: QS
authors.lastname: Mi
authors.forename: Ana
authors.initials: A
authors.lastname: Lustig
authors.forename: Dennis D
authors.initials: DD
authors.lastname: Taub
authors.forename: Dan L
authors.initials: DL
authors.lastname: Longo
authors.forename: James J
authors.initials: JJ
authors.lastname: Kenny
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D016175:B-Lymphocyte Subsets / Q000276:immunology* / Q000378:metabolism*; D001665:Binding Sites / Q000235:genetics / Q000276:immunology; D018929:Cell Culture Techniques; D002999:Clone Cells; D018985:Epitopes, B-Lymphocyte / Q000235:genetics / Q000378:metabolism; D015328:Gene Rearrangement, B-Lymphocyte, Light Chain / Q000235:genetics; D006801:Humans; D007130:Immunoglobulin Idiotypes / Q000096:biosynthesis* / Q000235:genetics* / Q000378:metabolism; D007135:Immunoglobulin Variable Region / Q000096:biosynthesis / Q000235:genetics; D007145:Immunoglobulin kappa-Chains / Q000096:biosynthesis / Q000235:genetics; D008213:Lymphocyte Activation / Q000235:genetics; D051379:Mice; D008807:Mice, Inbred BALB C; D008809:Mice, Inbred C3H; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D008822:Mice, Transgenic; D008969:Molecular Sequence Data; D010767:Phosphorylcholine / Q000276:immunology* / Q000378:metabolism*; D013154:Spleen / Q000166:cytology / Q000276:immunology; D014407:Tumor Cells, Cultured
chemical_list: D018985:Epitopes, B-Lymphocyte; D007130:Immunoglobulin Idiotypes; D007135:Immunoglobulin Variable Region; D007145:Immunoglobulin kappa-Chains; D010767:Phosphorylcholine