V(D)J germline gene repertoire analysis of monoclonal D antibodies and the implications for D epitope specificity.
BACKGROUND
The D antigen is a highly immunogenic human RBC antigen. Alloimmunization against the D antigen produces high-affinity antibodies that cause hemolytic transfusion reactions and HDN.


METHODS
Cloning and subsequent sequence analysis of 11 new samples of monoclonal anti-D was performed in an attempt to identify V(D)J germline gene usage. Sequences were compared and analyzed with 37 previously published samples of anti-D for identification of V(H) and V(L) pairings, canonical structures, and conformation of restricted germline gene usage.


RESULTS
The V(H) and V(L) pairings used by the new D MoAbs resulted in seven canonical combinations, three of which had not been described previously. Preferential usage of gene segments from the VH3 and VH4 families and of D3, D6, JH6, and DPK9 germline gene segments was also determined. Three samples of anti-D from different donors were found to use similar V(H) and V(kappa) germline genes, despite the fact that two of the antibodies recognized epD6/7 and the third recognized epD1. From the cumulative analysis of the anti-D IgG, 24 V(H) and V(L) gene pairings were identified, resulting in only 10 canonical structures.


CONCLUSIONS
Despite the potential for diversity, only a minority of V(H) and V(L) germline genes are used by anti-D. Consequently, V(H) and V(L) pairings and the resulting canonical structures are similarly restricted.
Department of Medicine and Therapeutics, University of Aberdeen, UK.
W S
WS
Perera
M T
MT
Moss
S J
SJ
Urbaniak
D000595:Amino Acid Sequence; D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology*; D000918:Antibody Specificity; D018604:Epitope Mapping; D005803:Genes, Immunoglobulin; D006801:Humans; D007135:Immunoglobulin Variable Region / Q000235:genetics* / Q000276:immunology*; D051379:Mice; D008969:Molecular Sequence Data; D012204:Rh-Hr Blood-Group System / Q000276:immunology*; D016415:Sequence Alignment
D000911:Antibodies, Monoclonal; D007135:Immunoglobulin Variable Region; D012204:Rh-Hr Blood-Group System; C026410:Rho(D) antigen