The IgM-associated protein mb-1 as a marker of normal and neoplastic B cells

J Immunol. 1991 Dec 1;147(11):2474-82.


Recent evidence indicates that the transmembrane form of IgM on murine and human B lymphocytes is physically associated with at least two proteins, forming a disulfide-linked dimer, which may control cell surface expression of IgM and also play a role in signal transduction after Ag binding (by analogy with the TCR-associated CD3 components in T lymphocytes). We have used mAb and polyclonal antibodies against an intracytoplasmic epitope on one of these polypeptides (previously identified in murine B cells as the product of the B cell specific mb-1 gene) to study the distribution of the IgM-associated dimer in human cells. By immunocytochemical staining of normal and neoplastic B cells, we show that the human mb-1 protein appears early in B cell differentiation, probably before expression of cytoplasmic mu-chain, and persists until the plasma cell stage, where it is seen as an intracytoplasmic component. According to immunohistologic analysis of reactive lymphoid tissue and lymphoma samples, mb-1 protein is completely B cell specific. Anti-mb-1 also labels B cell areas in tissues from seven different mammalian species. Finally, the Ig-associated dimer could be isolated from human hairy-cell leukemia cells in high purity and yield by affinity chromatography using anti-mb-1 antibody. Mice immunized with this material have produced a strong polyclonal response, so that it should now be possible to prepare a panel of new mAb reactive with different epitopes on both mb-1 and on its associated polypeptide(s).

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't
  • Corrected and Republished Article

MeSH terms

  • Animals
  • Antibodies, Monoclonal / immunology
  • Antigens, CD*
  • Antigens, Differentiation, B-Lymphocyte / chemistry*
  • Antigens, Differentiation, B-Lymphocyte / metabolism
  • B-Lymphocytes / physiology*
  • Biomarkers*
  • Biomarkers, Tumor*
  • Blotting, Western
  • Bone Marrow Cells
  • CD79 Antigens
  • Cell Differentiation
  • Chromatography, Affinity
  • Flow Cytometry
  • Hematopoietic Stem Cells / cytology
  • Hematopoietic Stem Cells / physiology*
  • Humans
  • Immunoenzyme Techniques
  • Immunoglobulin M / metabolism*
  • Lymphoma / immunology*
  • Membrane Glycoproteins / chemistry
  • Membrane Glycoproteins / isolation & purification
  • Membrane Glycoproteins / physiology*
  • Precipitin Tests
  • Receptors, Antigen, B-Cell*
  • Species Specificity


  • Antibodies, Monoclonal
  • Antigens, CD
  • Antigens, Differentiation, B-Lymphocyte
  • Biomarkers
  • Biomarkers, Tumor
  • CD79 Antigens
  • CD79A protein, human
  • Immunoglobulin M
  • Membrane Glycoproteins
  • Receptors, Antigen, B-Cell