Characterization of Natural Suppressor Cells in Human Bone Marrow

Abstract

Natural suppressor (NS) cells, which exert nonspecific suppressive activity in an unprimed manner, have been found in mouse, rabbit and monkey bone marrow (BM). In the present study, we characterize NS cells in human BM. NS activity was found in a fraction of low density (1.055-1.065 g/ml) BM

Early myeloid cells are high producers of nitric oxide upon CD40 plus IFN-γ stimulation through a mechanism dependent on endogenous TNF-α and IL-1α

“…These features indicate that the NOproducing cells under study share markers with early hematopoietic cells (WGA, ER-MP12) [25] of myeloid lineage (Gr-1, Mac-1 low , ER-MP20) [25,[27][28][29][30][31]. These results support the recent characterization of BM natural suppressor cells as myeloid progenitors [12]. Indeed, BM natural suppressor activity had been associated with hematopietic progenitors, because of their reactivity with WGA [9,17], responsiveness to colony-stimulating factors [31,32] and enrichment within GM-CFU cells [18].…”

“…+ cells producing NO upon CD40 plus IFN-q activation bear markers of myeloid progenitors BM-derived natural suppressor cells have been characterized recently as early myeloid cells [12]. To assess the phenotypic features of NO-producing cells within the Fr3-WGA + cell fraction, we took advantage of the conceivable presence of CD40 + cells in this BM cell population.…”

“…As CD40-CD154 interactions may induce NO production by macrophages [9,10] and dendritic cells [11], we have addressed if this can be also the case for Fr3-WGA + cells. Moreover, as BM natural suppressor cells have been shown recently with features of myeloid progenitors [12], we were prompted to characterize phenotypi- Fig. 1.…”

Opposing effects of fibrosarcoma cell‐derived IL‐1α and IL‐1β on immune response induction

“…[49][50][51][52] As already mentioned, TGFb expression is high in IL-1a 2/2 , IL-1b-competent tumors (unpublished observation). Furthermore, SC of mice bearing IL-1b-competent tumors also contain a higher percentage of TGFb and IL-10 expressing cells than SC of mice bearing IL1b 2/2 or IL-1ab 2/2 tumors.…”

Soluble factor and cell-cell interaction in cytostasis induced by bone marrow cells

“…Antiproliferative activity of bone marrow cytostatic effectots is not restricted by major histocompatibility complex antigens and is realized without cell lysis [1,2,[7][8][9][10][11]. These effectors do not express surface markers of immunocompetent cells, but possess some properties typical of natural immunosuppressor cells [4,10]. Soluble suppressor factors play the major role in the inhibition of tumor growth by BMC.…”