Eosinophil chemotactic factor release from neutrophils induced by stimulation with Schistosoma japonicum eggs.

The neutrophil is one of the sources of eosinophil chemotactic factor (ECF) in the presence of some stimulants. In the present study we showed that guinea-pig neutrophils could release ECF upon stimulation with Schistosoma japonicum eggs. ECF release from neutrophils began as early as 5 min after the stimulation and reached a peak at 20 min. When homogenate of the eggs was separated into a water-soluble fraction as soluble egg antigen (SEA) and a water-insoluble fraction (eggshell), both preparations possessed a potent neutrophil-stimulating activity to release ECF. The ECF release was dependent on the concentration of eggshells or SEA or on the number of neutrophils. The neutrophil-stimulating activity of eggshells was stable to heat, HCl, or pronase treatment but sensitive to NaOH treatment. When the eggs or eggshells were washed with acetone or Tween-20, they lost the neutrophil-stimulating activity to release ECF, indicating that the neutrophil-stimulating factor (NSF) possesses a lipid nature. The molecular weight of NSF extracted from the eggshells was estimated to be about 1000 Da by gel chromatography on Sephadex G25. The possible role of eggshells in the formation of eosinophil-rich granulomatous lesions in schistosomiasis japonica is discussed.

Temporary appearance of a circulating granulocyte-macrophage colony-stimulating factor in lethal murine malaria.

Infection of mice with Plasmodium berghei engendered a temporary appearance of granulocyte-macrophage colony-stimulating factor (GM-CSF) in the serum. The peak of GM-CSF levels was detected at day 2 post-infection, and then gradually decreased. On the other hand, the number of committed stem cells for granulocytes and macrophages (CFU-GM) in bone marrow transiently decreased at day 2 post-infection, and then increased and peaked at day 6 post-infection. When the serum of P. berghei-infected mice was fractionated by gel chromatography on Sephacryl S-300, GM-CSF activity was detected as a single peak with an apparent molecular weight of 64 KDa. GM-CSF was entirely adsorbed to concanavalin A-Sepharose 4B affinity chromatography, and was sensitive to pronase digestion, indicating its glycoprotein nature. These results suggest that the circulating GM-CSF would contribute the increase of granulocyte-macrophage hemopoiesis in the early phase of malaria.