The recurrent expression of variable region segments in human IgM anti-DNA autoantibodies.
RNA sequences for the V regions of human hybridoma-produced autoantibodies were determined by primer extension with reverse transcriptase. The sequencing of IgM autoantibodies from a leprosy patient revealed examples of recurrent use of V region gene segments in different autoantibodies from this patient and a previously studied patient with SLE. Moreover, several gene segments used in these autoantibodies show little alteration from germ-line sequences. mAb TH3, from a patient with leprosy, binds denatured DNA and poly(dT). The center of its H chain CDR35 has a sequence identical to that found previously in two anti-DNA antibodies from a lupus patient; these identities and their overlapping with two other published sequences define a human D-gene segment of approximately 25 nucleotides. Autoantibody TH9, from a leprosy patient, does not bind DNA. Its VH sequence has 87% identity with a VHI anti-DNA antibody, but differs from it markedly in the CDR1 region. TH9 also has a different H chain CDR3. The closely related JH4 or JH5 gene segments are expressed in five lupus or leprosy autoantibodies. In four of the antibodies, examples of V kappa 1, V kappa 3, or V kappa 4 and J kappa 2, or J kappa 5 segments were found. Two distinct leprosy-derived anti-DNA antibodies, 8E10 and TH3, share a completely identical V kappa sequence. This sequence differs in only two positions from that of a germ-line RF L chain gene. Several gene segments that are close to the germ line in sequence encode Ig V regions with autoantibody reactivity. These results provide a base line for determining whether these genes are precursors of more highly diversified antibodies that may be pathogenic in patients with SLE.
Dersimonian
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Department of Biochemistry, Tufts University Health Science Campus, Boston, MA 02111.
McAdam
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Mackworth-Young
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Stollar
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BD
D000595:Amino Acid Sequence; D000974:Antibodies, Antinuclear / Q000235:genetics* / Q000302:isolation & purification; D001327:Autoimmune Diseases / Q000235:genetics / Q000276:immunology; D001483:Base Sequence; D001666:Binding Sites, Antibody; D004247:DNA / Q000276:immunology; D006801:Humans; D006825:Hybridomas / Q000032:analysis; D007143:Immunoglobulin Heavy Chains / Q000235:genetics / Q000302:isolation & purification; D007075:Immunoglobulin M / Q000235:genetics* / Q000302:isolation & purification; D007135:Immunoglobulin Variable Region / Q000235:genetics* / Q000302:isolation & purification; D007145:Immunoglobulin kappa-Chains / Q000235:genetics / Q000302:isolation & purification; D007918:Leprosy / Q000235:genetics / Q000276:immunology; D008969:Molecular Sequence Data
D000974:Antibodies, Antinuclear; D007143:Immunoglobulin Heavy Chains; D007075:Immunoglobulin M; D007135:Immunoglobulin Variable Region; D007145:Immunoglobulin kappa-Chains; D004247:DNA