Expression of the immunoglobulin VH gene 51p1 is proportional to its germline gene copy number

J Clin Invest. 1996 May 1;97(9):2074-80. doi: 10.1172/JCI118644.


51p1 is an immunoglobulin VH gene that is frequently expressed in B cell chronic lymphocytic leukemia and early in B cell ontogeny. The 51p1 gene locus is highly polymorphic, consisting of 13 alleles that can be classified as being either 51p1-related or hy1263-related, based on distinctive sequence motifs in the second complementarity determining region. Two of the 51p1-related genes usually occur as a linked pair on the same haopltype, resulting from gene duplication. Consequently, a person can have a total of zero to four copies of 51p1-related genes. These genes are detectable in genomic DNA by sequence-specific RFLP analysis using oligonucleotide probes. Ig encoded by nonmutated 51p1-related genes can be detected by G6, a murine antiidiotypic mAb. We have now studied lymphocytes from 35 human tonsils to examine the relation between the number of 51p1-related germlime gene copies and the proportion of IgD-bearing tonsillar B cells that react with G6. All subjects who had zero copies of 51p1-related genes lacked any G6-reactive B cells, whereas those with four copies of 51p1-related genes had the highest proportions of G6-positive IgD B cells, up to 11.4%. Subjects with intermediate gene doses had intermediate proportions of G6-reactive B cells. Over the entire data set, the percentage of IgD-bearing B cells that reacted with G6 was proportional to the 51p1-related gene copy number (r = 0.92, p < 0.001), with each copy accounting for 2.4-4.0% of the IgD-bearing B cells. We conclude that 51p1-related genes are expressed by a relatively large percentage of IgD+ tonsillar B cells and this percentage is proportional to the germline copy number of 51p1-related genes.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Adult
  • B-Lymphocytes / immunology*
  • B-Lymphocytes / pathology
  • Base Sequence
  • Cell Count
  • Cell Differentiation / genetics
  • Gene Dosage*
  • Haplotypes
  • Humans
  • Immunoglobulin Variable Region / genetics*
  • Immunoglobulin Variable Region / immunology
  • Molecular Sequence Data
  • Palatine Tonsil / immunology*
  • Palatine Tonsil / pathology
  • Tonsillitis / immunology
  • Tonsillitis / pathology


  • Immunoglobulin Variable Region