title: Analyses of recombinant stereotypic IGHV3-21-encoded antibodies expressed in chronic lymphocytic leukemia.
abstract: Chronic lymphocytic leukemia (CLL) cells that use IgH encoded by IGHV3-21 and that have a particular stereotypic third CDR (HCDR3), DANGMDV (motif-1), almost invariably express Ig L chains (IgL) encoded by IGLV3-21, whereas CLL that use IGHV3-21-encoded IgH with another stereotypic HCDR3, DPSFYSSSWTLFDY (motif-2), invariably express κ-IgL encoded by IGKV3-20. This nonstochastic pairing could reflect steric factors that preclude these IgH from pairing with other IgL or selection for an Ig with a particular Ag-binding activity. We generated rIg with IGHV3-21-encoded IgH with HCDR3 motif-1 or -2 and IgL encoded by IGKV3-20 or IGLV3-21. Each IgH paired equally well with matched or mismatched κ- or λ-IgL to form functional Ig, which we screened for binding to an array of different Ags. Ig with IGLV3-21-encoded λ-IgL could bind with an affinity of ∼ 2 × 10(-6) M to protein L, a cell-wall protein of Peptostreptococcus magnus, independent of the IgH, indicating that protein L is a superantigen for IGLV3-21-encoded λ-IgL. We also detected Ig binding to cofilin, a highly conserved actin-binding protein. However, cofilin binding was independent of native pairing of IgH and IgL and was not specific for Ig with IgH encoded by IGHV3-21. We conclude that steric factors or the binding activity for protein L or cofilin cannot account for the nonstochastic pairing of IgH and IgL observed for the stereotypic Ig made by CLL cells that express IGHV3-21.
authors.affiliation: Moores University of California San Diego Cancer Center, La Jolla, CA 92093-0820, USA.
authors.forename: Emanuela M
authors.initials: EM
authors.lastname: Ghia
authors.forename: George F
authors.initials: GF
authors.lastname: Widhopf
authors.forename: Laura Z
authors.initials: LZ
authors.lastname: Rassenti
authors.forename: Thomas J
authors.initials: TJ
authors.lastname: Kipps
mesh_terms: D051339:Actin Depolymerizing Factors / Q000276:immunology / Q000378:metabolism; D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000276:immunology / Q000378:metabolism; D001667:Binding, Competitive; D015153:Blotting, Western; D005434:Flow Cytometry; D006801:Humans; D007143:Immunoglobulin Heavy Chains / Q000235:genetics / Q000276:immunology* / Q000378:metabolism; D007147:Immunoglobulin Light Chains / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D007135:Immunoglobulin Variable Region / Q000235:genetics / Q000276:immunology* / Q000378:metabolism; D007145:Immunoglobulin kappa-Chains / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D007700:Kinetics; D015451:Leukemia, Lymphocytic, Chronic, B-Cell / Q000235:genetics / Q000276:immunology* / Q000378:metabolism; D040081:Protein Array Analysis; D011485:Protein Binding; D011994:Recombinant Proteins / Q000276:immunology* / Q000378:metabolism
chemical_list: D051339:Actin Depolymerizing Factors; D001426:Bacterial Proteins; C055047:Ig L-binding protein, Peptostreptococcus; D007143:Immunoglobulin Heavy Chains; D007147:Immunoglobulin Light Chains; D007135:Immunoglobulin Variable Region; D007145:Immunoglobulin kappa-Chains; D011994:Recombinant Proteins