In order to investigate the capacity of monocytes to release erythroid burst-promoting activity (BPA), we added media conditioned by homologous monocytes to both serum-free human and serum-restricted murine marrow culture. We found that soluble, membrane vesicle-free culture medium is a potent source of the growth factor. On the other hand, monocyte membranes or exfoliated plasma membrane vesic...

Tumor necrosis factor-alpha (TNF alpha) is a cytokine with multiple biological functions which, in mammals, has been shown to modulate muscle and adipose tissue metabolism. In fish, TNF alpha has been identified in several species. However, few studies have examined the role of TNF alpha in fish outside the immune system. In this study, we assessed the effects of human recombinant TNF alpha and...

Spinal cord neurons cultured in vitro have been shown to respond to changes in their environment by means of 2 different types of neurite outgrowth: (1) neurite elongation and (2) emergence and branching of newly formed neurites. Culture of spinal cord neurons with heparan sulfate proteoglycan (HSPG) medium resulted in a 3-fold increase in neurite elongation compared to the control. Extensive b...

Human monocyte/macrophages (Mphi) exposed to nonparticulate stimuli can express cell surface Fas ligand (FasL) and release active soluble FasL (sFasL). We now report that monocyte/Mphi-ingesting opsonized zymosan released sFasL and conditioned supernatants so that these triggered Fas-mediated apoptosis of "bystander" monocytes and FasL-negative neutrophils. Furthermore, identical results were s...

Human peripheral blood monocytes and tumor-associated macrophages release a factor that enhances the clonal growth of a human epithelial tumor cell line (SW-13) in soft agar. We now demonstrate that purified interleukin 1 (IL-1) may account for part of this colony-stimulating activity. Purified IL-1 (0.5 to 8 units/ml) was added to SW-13 cells cultured in soft agar. IL-1 increased colony growth...

Human umbilical vein endothelial cells were cultured in supernatants of peripheral blood monocytes that had been cultured for 3 days with and without lactoferrin. Colonystimulating activity (CSA) was measured in supernatants of the endothelial cell cultures and appropriate control cultures using normal. T-Iymphocyte-depleted. phagocytedepleted, low-density bone marrow cells in colony growth (CF...

The molecular mechanisms that underlie the axonal damage that accompanies CNS inflammation are largely unknown. Here, we investigate the effects of immune cells on neuronal viability and axonal growth and show that conditioned media from myeloid lineage cells inhibit neurite outgrowth without causing apoptosis. Treatment with monocyte conditioned medium enhances myosin light chain phosphorylati...