PG-M1: a new monoclonal antibody directed against a fixative-resistant epitope on the macrophage-restricted form of the CD68 molecule

Am J Pathol. 1993 May;142(5):1359-72.


A new anti-macrophage monoclonal antibody (PG-M1) was produced by immunizing BALB/c mice with fresh spleen cells from a patient with Gaucher's disease. PG-M1 reacts strongly with a fixative-resistant epitope of an intracytoplasmic molecule, selectively expressed by virtually all macrophages of the human body. Although attempts to immunoprecipitate the molecule recognized by PG-M1 have failed so far, the reactivity of the antibody with COS-1 and WOP cells transfected with a human complementary DNA clone encoding for the CD68 antigen suggests that PG-M1 is a new member of the CD68 cluster. However, unlike other CD68 antibodies (KP1, EBM11, etc.), which react with both macrophages and myeloid cells, PG-M1 detects a fixative-resistant epitope on the macrophage-restricted form of the CD68 antigen. In 957 routinely fixed, paraffin-embedded samples, PG-M1 showed a more restricted reactivity with elements of the monocyte/macrophage lineage than the previously described monoclonal antibodies MAC-387 (anti-calgranulins), KP1 (CD68) and Ki-M1P. Among hematological malignancies, PG-M1 only labels acute leukemias of M4 and M5 type and rare examples of malignant histiocytosis/true histiocytic sarcoma. In contrast, acute leukemias of the M1, M2, M3, M6, M7, and L1-L3 types, non-Hodgkin's lymphomas, and Hodgkin and Reed-Sternberg cells of Hodgkin's disease are consistently PG-M1-negative. In the daily diagnostic practice, PG-M1 seems to be particularly valuable for the diagnosis of myelomonocytic or monocytic leukemia and neoplasms of true histiocytic origin in routine paraffin sections.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Antibodies, Monoclonal / immunology*
  • Antibody Formation
  • Antigens, CD / analysis
  • Antigens, CD / immunology*
  • Antigens, Differentiation, Myelomonocytic / analysis
  • Antigens, Differentiation, Myelomonocytic / immunology*
  • Cell Line
  • DNA / genetics
  • Drug Resistance
  • Epitopes*
  • Fixatives / pharmacology*
  • Hematologic Diseases / immunology
  • Hematopoietic System
  • Humans
  • Inflammation / immunology
  • Lymphatic Diseases / immunology
  • Macrophages / immunology*
  • Neoplasms / immunology
  • Precipitin Tests
  • Reference Values
  • Transfection


  • Antibodies, Monoclonal
  • Antigens, CD
  • Antigens, Differentiation, Myelomonocytic
  • CD68 antigen, human
  • Epitopes
  • Fixatives
  • DNA