Submitted May 22, 2006
Accepted July 24, 2006
Receptor type tyrosine phosphatase gamma (PTP
), a
new identifier for myeloid dendritic cells and specialized
macrophages
Daniele Lissandrini, William Vermi, Marzia Vezzalini, Silvano Sozzani, Fabio Facchetti, Graziella Bellone, Andrea Mafficini, Francesca Gentili, Maria Grazia Ennas, Cristina Tecchio, and Claudio Sorio*
Department of Pathology, University of Verona, Italy
Department of Pathology, Spedali Civili, Brescia, Italy
Department of Pathology, University di Verona, Italy
Department of Biotechnology, Section of General Pathology and Immunology, University of Brescia, Ita
Department of Clinical Physiopathology, University of Turin, Italy
Department of Cytomorphology, University of Cagliari, Italy
* Corresponding author; email: claudio.sorio{at}univr.it.
Protein tyrosine phosphatase (PTP)
is a receptor-like molecule with a known role in murine hematopoiesis. We analyzed the regulation of PTP expression in the human hematopoietic system, where it was detected in human peripheral blood monocyte and dendritic cells (DC) of myeloid and plasmacytoid phenotype. Its expression was maintained during monocyte differentiation in vitro (moDC) and was further increased following maturation with bacterial lipopolysaccaride (LPS), CD40L and TNF?. On the contrary PTP was absent when monocytes from the same donor were induced to differentiate in macrophages. B and T lymphocytes did not express PTP. PTP mRNA was expressed in primary and secondary lymphoid tissues, with the highest expression in the spleen. PTP was detected by immunohistochemistry in subsets of myeloid-derived dendritic cells and specialized macrophages (tingible bodies, sinus and alveolar macrophages). Classic macrophages either infective or reactive present in granulomatous reactions did not express PTP. Decreased capability to induce proliferation and interferon gamma secretion in T cell by moDC from patients affected by advanced pancreatic cancer was found associated to increased PTP expression. Taken together, these results indicate that PTP is a protein finely regulated in dendritic cell and macrophage subsets in vitro and in vivo.
