Receptor type tyrosine phosphatase gamma (PTP gamma) is a novel dendritic cell marker

In the present study we evaluated PTPgamma expression in the human hematopoietic system. PTPgamma mRNA expression is highest in spleen and, to a lesser extent, thymus. PTPgamma expression was detected in large, dendritic elements in these and all the other hemopoietic and non-hemopoietic tissues analyzed. Their phenotypic characterization was in agreement with immature, tissue-localized myeloid-derived dendritic cells (CD11c(+), Mannose Receptor(+), DC-SIGN(+), CD1a(-)). Confocal microscopy analysis demonstrate its cell membrane localization in in vitro cultured dendritic cells. In the same cellular model other receptor type tyrosine phosphatases (CD45, CD 148 and PTPepsilon) were differentially regulated upon lipopolisaccaride treatment. Taken together these results point to a highly selective expression and modulation of this receptor-type tyrosine phosphatase in a myeloid DC subset and a potential role in the regulation of immune response, providing a novel too] to unravel the complex biology of these cells.