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Aminopeptidase N: a constitutive cell-surface protein on human dermal fibroblasts

T H Piela-Smith1, J H Korn

  • 1Division of Rheumatic Diseases, Veterans Administration Medical Center, Newington, Connecticut, USA.

Cellular Immunology
|April 15, 1995
PubMed

Insights

Researchers identified aminopeptidase N (hAPN) on human dermal fibroblasts, revealing new enzymatic properties and a broader cellular distribution for this enzyme beyond its previously known hematopoetic cell marker role.

Area of Science:

  • Immunology
  • Biochemistry
  • Cell Biology

Background:

  • Monoclonal antibodies are crucial tools for identifying cell surface antigens.
  • Aminopeptidase N (hAPN) was primarily recognized as a marker for hematopoetic cells.
  • Understanding antigen expression on fibroblasts is key to characterizing their function.

Purpose of the Study:

  • To investigate differential antigen expression on human dermal fibroblast clones.
  • To identify and characterize membrane proteins on fibroblasts using monoclonal antibodies.
  • To determine the presence and role of aminopeptidase N (hAPN) in dermal fibroblasts.

Main Methods:

  • Development of monoclonal antibodies against human dermal fibroblast cell-surface membranes.
  • Limited dilution cloning of fibroblasts to assess differential antigen expression.
  • Protein identification via sequence analysis of immunoprecipitates.
  • Biochemical assays, electron microscopy, flow cytometry, and ELISA for characterizing hAPN expression.

Main Results:

  • A monoclonal antibody, BR2, was identified, recognizing aminopeptidase N (hAPN).
  • hAPN was found to be abundantly expressed on human dermal fibroblasts.
  • Fibroblast expression of hAPN confers previously unrecognized enzymatic properties.
  • The cellular distribution of hAPN is demonstrated to be wider than previously understood.

Conclusions:

  • Human dermal fibroblasts express abundant aminopeptidase N (hAPN).
  • hAPN expression imparts novel enzymatic functions to dermal fibroblasts.
  • The findings expand the known cellular localization of hAPN, indicating a broader biological role.

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