Specificity and idiotope expression of IgM produced by CD5+ and CD5- cord blood B-cell clones

Ann N Y Acad Sci. 1992 May 4:651:527-39. doi: 10.1111/j.1749-6632.1992.tb24659.x.

Abstract

Epstein-Barr virus (EBV)-immortalized monoclonal B-cell lines were established from CD5+ and CD5- cord-blood B cells. IgM from many of both CD5+ and CD5- clones reacted with IgG-Fc, ssDNA, and a variety of other autoantigens. More CD5+ B cells that used light chains of the kappa isotype reacted with IgG-Fc and ssDNA than kappa-bearing CD5- B cells. Because many of the clones reacted with IgG-Fc, they were analyzed for the expression of cross-reactive idiotypes (CRI) associated with rheumatoid factor and cold agglutinin paraproteins using murine antibodies (mAb) recognizing V kappa and VH subgroup-associated determinants. Expression of the V kappa IIIb sub-subgroup-associated idiotope recognized by 17.109 mAb was expressed at significantly higher frequency (32%; p less than 0.05) and IgM antibodies derived from the CD5+ compared with the CD5- clones (5%). Both CD5+ and CD5- clones expressed the RF paraprotein-associated idiotope recognized by G8 mAb to the same extent. Similar results were obtained using binding to SpA as a marker of VH III family usage. Furthermore, no differences in frequency of expression of RF paraprotein-associated idiotopes recognized by B6 and/or D12, and characteristic of some antibodies using VH III family genes, were found between the CD5+ and CD5- populations. Although a higher than expected frequency of VH IV-gene expression was demonstrated (around 30%) in both CD5+ and CD5- cells, there were differences in expression of CRI recognized by mAb Lc1 and R2.1A2 with specificities for two VH IV subfamilies. While some CD5+ and CD5- clones were identified in which their IgM reacted with mAb Lc1, only CD5+ clones were recognized by another mAb R2.1A2. Analysis of the relationships between antigen specificities and V kappa- and VH-family gene usage indicated that auto- or polyreactivity was not associated with V kappa III nor any particular VH family. The higher frequency of the V kappa IIIb sub-subgroup-associated idiotope recognized by 17-109 in the CD5+ clones and the association of CD5+ B cells with the VH IV subfamily recognized by mAb R2.1A2 and 9G4 may suggest that CD5+ B cells in cord blood are expanded as a result of recruitment within the fetal environment.

Publication types

  • Research Support, Non-U.S. Gov't
  • Review

MeSH terms

  • Animals
  • Antigens, CD / analysis
  • Antigens, CD / immunology*
  • B-Lymphocytes / immunology*
  • CD5 Antigens
  • Clone Cells
  • Fetal Blood / immunology*
  • Gene Expression
  • Genes, Immunoglobulin*
  • Herpesvirus 4, Human / immunology
  • Immunoglobulin Heavy Chains / genetics
  • Immunoglobulin Idiotypes / genetics*
  • Immunoglobulin M / genetics*
  • Immunoglobulin Variable Region / genetics
  • Mice
  • Multigene Family

Substances

  • Antigens, CD
  • CD5 Antigens
  • Immunoglobulin Heavy Chains
  • Immunoglobulin Idiotypes
  • Immunoglobulin M
  • Immunoglobulin Variable Region