A rheumatoid factor from a normal individual encoded by VH2 and V kappa II gene segments.
OBJECTIVE
To gain insight into the immunoglobulin variable-region repertoire of anti-IgG antibodies (rheumatoid factors [RF]), we characterized the VH and V kappa gene segments utilized in an IgM-RF-secreting lymphoblastoid cell line (SSH23) isolated from a normal individual.


METHODS
The cell line SSH23 was established by Epstein-Barr virus transformation of peripheral blood non-T mononuclear cells. First-strand complementary DNA (cDNA) was generated and used for polymerase chain reaction amplification of the heavy and light chain variable domains. The amplified variable domains were sequenced and compared with an extensive database of germline and cDNA V gene segments.


RESULTS
The VH sequence was found to be identical to a previously described fetal VH2 incomplete cDNA and to differ by only 3 nucleotides from a JH proximal germline VH2 gene segment. To our knowledge, this is the first example of a VH2 rheumatoid factor. The V kappa 2-J kappa 4 light chain contains an uncommon 10-amino acid third complementarity-determining region (CDR 3).


CONCLUSIONS
Utilization of preimmune fetal VH gene segments and unusual light chain junctional diversity appear to be features shared by many physiologic and pathologic rheumatoid factors.
Stüber
F
F
Division of Clinical Immunology, University of Alabama, Birmingham.
Lee
S K
SK
Bridges
S L
SL
Koopman
W J
WJ
Schroeder
H W
HW
Gaskin
F
F
Fu
S M
SM
D000595:Amino Acid Sequence; D001483:Base Sequence; D002461:Cell Line, Transformed; D004247:DNA / Q000032:analysis / Q000235:genetics; D005803:Genes, Immunoglobulin / Q000235:genetics*; D004854:Herpesvirus 4, Human; D006801:Humans; D007143:Immunoglobulin Heavy Chains / Q000235:genetics*; D007135:Immunoglobulin Variable Region / Q000235:genetics*; D007145:Immunoglobulin kappa-Chains / Q000235:genetics*; D008214:Lymphocytes / Q000166:cytology; D008969:Molecular Sequence Data; D012217:Rheumatoid Factor / Q000235:genetics*; D013234:Stem Cells / Q000166:cytology; D014158:Transcription, Genetic
D007143:Immunoglobulin Heavy Chains; D007135:Immunoglobulin Variable Region; D007145:Immunoglobulin kappa-Chains; D004247:DNA; D012217:Rheumatoid Factor