Naturally occurring anti-i/I cold agglutinins may be encoded by different VH3 genes as well as the VH4.21 gene segment.
In the current study, we wished to determine if the V regions encoding the naturally occurring anti-i/I Cold Agglutinins (anti-i/I CA) differ from pathogenic anti-i/I CA that are exclusively encoded by the VH4.21 gene. After EBV transformation of B lymphocytes, we generated one anti-I secreting clone from each of two individuals; clone 4G (individual CM, PBL) and clone Sp1 (individual SC, spleen). Clone 4G expresses a VH3 gene sequence that is 92% homologous to the germline gene WHG26. Clone Sp1 also expresses a VH3 gene that is 98% homologous to the fetally rearranged M85/20P1 gene. Another clone, Sp2 (anti-i specificity), from individual SC is 98% homologous to the germline gene VH4.21. For correlation, we studied anti-i/I CA fractions purified from 15 normal sera and found no or relatively small amounts of 9G4 (VH4.21 related idiotype) reactive IgM. Five cold agglutinin fractions contained large amounts of VH3-encoded IgM (compared to pooled normal IgM) by virtue of their binding to modified protein Staph A (SPA), and absorption of three CA fractions with modified SPA specifically removed anti-i/I binding specificity entirely. Collectively, the data indicate that naturally occurring anti-i/I CA may be encoded to a large extent by non-VH4.21-related genes, and that the VH4.21 gene is not uniquely required for anti-i/I specificity.
Jefferies
L C
LC
Hospital of the University of Pennsylvania, Department of Pathology and Laboratory Medicine, Philadelphia 19104.
Carchidi
C M
CM
Silberstein
L E
LE
D000373:Agglutinins / Q000096:biosynthesis* / Q000235:genetics*; D000595:Amino Acid Sequence; D000911:Antibodies, Monoclonal; D001402:B-Lymphocytes / Q000276:immunology*; D001483:Base Sequence; D002461:Cell Line, Transformed; D002999:Clone Cells; D003080:Cold Temperature; D003450:Cryoglobulins; D017931:DNA Primers; D018076:DNA, Complementary / Q000378:metabolism; D004854:Herpesvirus 4, Human / Q000235:genetics; D006801:Humans; D007075:Immunoglobulin M / Q000096:biosynthesis; D007438:Introns; D008223:Lymphoma / Q000276:immunology / Q000378:metabolism; D008969:Molecular Sequence Data; D005810:Multigene Family; D016133:Polymerase Chain Reaction; D021382:Protein Sorting Signals / Q000235:genetics
D000373:Agglutinins; D000911:Antibodies, Monoclonal; D003450:Cryoglobulins; D017931:DNA Primers; D018076:DNA, Complementary; D007075:Immunoglobulin M; D021382:Protein Sorting Signals; C029443:cold agglutinins