Heavy chain dominance in the binding of DNA by a lupus mouse monoclonal autoantibody.
Antibodies H241 and 2C10 are lupus mouse IgG autoantibodies that bind native DNA. In previous experiments, oligonucleotide antigens affinity-labeled both H and L chains of H241 but only the H chain of antibody 2C10. Primary structures of the V regions of the 2C10 H and L chains and the H241 L chain, determined from cDNA, help to explain the previous affinity-labeling experiments. The 2C10 L chain CDRs had several Asp residues and a net negative charge of five, whereas the 2C10 H chain CDRs had four Arg residues and a net positive charge of five. The L chain CDRs of H241 had a net positive charge of one. [The H241 H chain cDNA sequence was published previously by Gangemi et al. (1993) J. Immun. 151, 4660-4671]. Plasmid vectors were used for bacterial expression of H and L chains of 2C10 alone and in combinations in single chain Fv (scFv) molecules. The H chain alone bound native DNA as well as or better than the H-plus-L chain scFv. The H chain alone also bound Z-DNA. Combination of the 2C10 H chain with the L chain of an anti-Z-DNA antibody maintained the selectivity for Z-DNA, whereas its combination with the 2C10 L chain (in the 2C10 Fab) yielded selective B-DNA binding. The results with 2C10 match other examples in which the H chain is sufficient for DNA binding but selectivity is modulated by the L chain. The H chain binding to autoantigen may reflect selective events in early stages of B cell development.
Jang
Y J
YJ
Department of Biochemistry, Tufts University School of Medicine, Boston, MA 02111, USA.
Lecerf
J M
JM
Stollar
B D
BD
D000595:Amino Acid Sequence; D000818:Animals; D000974:Antibodies, Antinuclear / Q000235:genetics / Q000378:metabolism*; D000911:Antibodies, Monoclonal / Q000235:genetics / Q000378:metabolism*; D001402:B-Lymphocytes / Q000276:immunology; D001483:Base Sequence; D003001:Cloning, Molecular; D004247:DNA / Q000276:immunology* / Q000378:metabolism*; D017931:DNA Primers / Q000235:genetics; D004926:Escherichia coli / Q000235:genetics; D007140:Immunoglobulin Fab Fragments / Q000235:genetics / Q000378:metabolism; D007074:Immunoglobulin G / Q000235:genetics / Q000378:metabolism; D007143:Immunoglobulin Heavy Chains / Q000235:genetics / Q000378:metabolism*; D007147:Immunoglobulin Light Chains / Q000235:genetics / Q000378:metabolism; D007135:Immunoglobulin Variable Region / Q000235:genetics / Q000378:metabolism; D008180:Lupus Erythematosus, Systemic / Q000235:genetics / Q000276:immunology* / Q000378:metabolism; D051379:Mice; D008969:Molecular Sequence Data; D016133:Polymerase Chain Reaction
D000974:Antibodies, Antinuclear; D000911:Antibodies, Monoclonal; D017931:DNA Primers; D007140:Immunoglobulin Fab Fragments; D007074:Immunoglobulin G; D007143:Immunoglobulin Heavy Chains; D007147:Immunoglobulin Light Chains; D007135:Immunoglobulin Variable Region; D004247:DNA