A specific monoclonal antibody (PG-B6) detects expression of the BCL-6 protein in germinal center B cells

Am J Pathol. 1995 Aug;147(2):405-11.

Abstract

The BCL-6 gene is frequently involved in translocations occurring at the 3q27 locus and is rearranged in approximately 30% of diffuse large cell lymphomas and in a small fraction of follicular lymphomas. The BCL-6 gene encodes for a Kruppel-type zinc-finger protein, the cell/tissue expression and function of which is unknown. In this study, we describe a new monoclonal antibody (PG-B6) that is specifically directed against a fixative-sensitive epitope on the amino-terminal region of the BCL-6 protein. By immunocytochemical analysis, BCL-6 localizes in the nucleus where PG-B6 staining gives a microgranular/diffuse pattern with exclusion of the nucleoli. The main reactivity of PG-B6 in tonsil and spleen is with the nuclei of germinal center B cells, whereas B cells within the mantle and marginal zones do not express BCL-6. No other lymphoid cells in the tonsil express BCL-6 except for a subset of CD3+/CD4+ intrafollicular and interfollicular T cells. A few lymphoid cells of unknown phenotype express BCL-6 in the thymus. Extra-lymphoid BCL-6 expression includes a weak nuclear positivity of epithelia. In non-Hodgkin's lymphomas, BCL-6 expression parallels that observed in normal lymphoid compartments, eg, expression in germinal center-derived tumors (follicular and diffuse large cell lymphomas), but not in mantle cell and marginal zone lymphomas. In most diffuse large cell lymphomas, the BCL-6 protein is expressed at high levels in cases with or without BCL-6 gene rearrangements. These findings indicate that BCL-6 expression is specifically regulated during B lymphocyte development and suggest that BCL-6 may play a role during B cell differentiation in the germinal center.

Publication types

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

MeSH terms

  • Animals
  • Antibodies, Monoclonal / immunology*
  • Antibody Specificity
  • B-Lymphocytes / metabolism*
  • DNA-Binding Proteins / immunology*
  • DNA-Binding Proteins / metabolism*
  • Lymphoid Tissue / cytology
  • Lymphoid Tissue / metabolism*
  • Lymphoma, B-Cell / metabolism*
  • Lymphoma, B-Cell / pathology
  • Lymphoma, Non-Hodgkin / metabolism
  • Mice
  • Mice, Inbred BALB C
  • Proto-Oncogene Proteins / immunology*
  • Proto-Oncogene Proteins / metabolism*
  • Proto-Oncogene Proteins c-bcl-6
  • Reference Values
  • Transcription Factors / immunology*
  • Transcription Factors / metabolism*

Substances

  • Antibodies, Monoclonal
  • DNA-Binding Proteins
  • Proto-Oncogene Proteins
  • Proto-Oncogene Proteins c-bcl-6
  • Transcription Factors