Monoclonal antibodies PG-B6a and PG-B6p recognize, respectively, a highly conserved and a formol-resistant epitope on the human BCL-6 protein amino-terminal region

Am J Pathol. 1996 May;148(5):1543-55.

Abstract

The human BCL-6 gene, which is rearranged in approximately 30% of diffuse large B cell lymphomas, encodes a 706-amino-acid nuclear protein of the Kruppel-type zinc finger transcription factors mainly expressed in normal germinal center B cells and related lymphomas. Four monoclonal antibodies (PG-B6, PG-B6a, PG-B6p, and PG-B6m), specifically directed against the human BCL-6 protein, were generated by immunizing BALB/c mice with a recombinant protein corresponding to the BCL-6 amino-terminal region (amino acids 3 to 484). The PG-B6 monoclonal antibody reacted with a BCL-6 epitope sensitive to fixatives and preserved in all mammalian species. PG-B6a (a is for avian) recognized the most evolutionarily conserved BCL-6 epitope (expressed in all animal species including avian). PG-B6p (p is for paraffin) recognized a fixative-resistant epitope of BCL-6 that was detectable on paraffin sections after microwave heating in 1 mmol/L EDTA buffer. PG-B6m (m is for mantle) was the least specific monoclonal antibody as, in addition to BCL-6, it reacted with a yet undefined antigen selectively located in the cytoplasm of mantle and marginal zone B cells. All monoclonal antibodies detected strong nuclear expression of BCL-6 in follicular lymphomas, diffuse large B cell lymphomas, Burkitt's lymphomas, and nodular, lymphocyte-predominance Hodgkin's disease. In diffuse large B cell lymphomas, BCL-6 expression was independent of BCL-6 gene rearrangements and did not correlate with expression of other markers or the proliferation index. BCL-6 was not expressed in B-CLL, hairy cell leukemia, mantle-cell- and marginal-zone-derived lymphomas. Labeling of paraffin sections with PG-B6p proved useful for differentiating proliferation centers in B-CLL (BCl-2+/BCL-6-) from trapped germinal centers in mantle cell lymphomas (BCL-2-/BCL-6+) and for identifying neoplastic cells in cases of nodular, lymphocyte-predominance Hodgkin's disease. Because of their high specificity, wide reactivity in humans and animal species including avians (PG-B6a), and suitability for labeling routine paraffin sections (PG-B6p), the reagents described in this paper should prove valuable in both research and diagnostics.

Publication types

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

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Antibodies, Monoclonal / immunology*
  • Cattle
  • Chickens
  • Columbidae
  • DNA-Binding Proteins / analysis*
  • DNA-Binding Proteins / immunology
  • DNA-Binding Proteins / metabolism
  • Epitopes / analysis*
  • Epitopes / immunology
  • Humans
  • Immunologic Techniques
  • Lymphoid Tissue / chemistry
  • Lymphoid Tissue / metabolism
  • Lymphoid Tissue / pathology
  • Lymphoma / chemistry
  • Lymphoma / diagnosis
  • Lymphoma / pathology
  • Mice
  • Mice, Inbred BALB C
  • Molecular Sequence Data
  • Palatine Tonsil / chemistry
  • Palatine Tonsil / pathology
  • Proto-Oncogene Proteins / analysis*
  • Proto-Oncogene Proteins / immunology
  • Proto-Oncogene Proteins / metabolism
  • Proto-Oncogene Proteins c-bcl-6
  • Rabbits
  • Rats
  • Sheep
  • Species Specificity
  • Spleen / chemistry
  • Spleen / pathology
  • Swine
  • Transcription Factors / analysis*
  • Transcription Factors / immunology
  • Transcription Factors / metabolism

Substances

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