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

Brunangelo Falini, Leonardo Flenghi, Stefano Pileri, Marcello Gambacorta, Barbara Bigerna, Horst Durkop, Florian Eitelbach, Juergen Thiele, Roberta Pacini, Antonio Cavaliere, Massimo Martelli, Nadia Cardarelli, Elena Sabattini, Simonetta Poggi, Harald Stein

Research output: Contribution to journalArticlepeer-review

Abstract

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 (anticalgranulins), 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-Strnmberg 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.

Original languageEnglish
Pages (from-to)1359-1372
Number of pages14
JournalAmerican Journal of Pathology
Volume142
Issue number5
Publication statusPublished - May 1993

ASJC Scopus subject areas

  • Pathology and Forensic Medicine

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