Phagocytosis involves the internalization of extracellular material by invagination of the plasma membrane to form intracellular vesicles called phagosomes, which have functions that include pathogen degradation. The degradative properties of phagosomes are thought to be conferred by sequential fusion with endosomes and lysosomes; however, this maturation process has not been studied in vivo. W...

Dopamine (DA) is a signal moiety bridging the nervous and immune systems. DA dysregulation is linked to serious human diseases, including addiction, schizophrenia, and Parkinson's disease. However, DA actions in the immune system remain incompletely understood. In this study, we found that DA modulates insect hemocyte phagocytosis using hemocytes prepared from the rice stem borer (RSB), Chilo s...

A modulation of the phagocytic activity of hemocytes from the common periwinkle Littorina littorea by secretory-excretory products (SEP) released by trematode rediae during axenic in vitro cultivation was studied. The SEP released by the parasites Himasthla elongata (Echinostomatidae) and Cryptocotyle lingua (Heterophyidae) were found to inhibit the phagocytosis of zymozan particles by periwink...

Insect blood cells (hemocytes) comprise an essential arm of the immune system [1-7]. Several factors mediating recognition and phagocytosis of foreign intruders by hemocytes have been identified, but the mechanisms regulating hemocyte movement remain fragmentary. Embryonic hemocytes from Drosophila migrate along stereotypical routes in response to chemotactic signals from PVF ligands, members o...

Insect hemocytes in response to lipopolysaccharide (LPS) of Gram-negative bacteria facilitate binding and internalization of either cell-associated or cell-free LPS (Charalambidis, N. D., Foukas L. C., and Marmaras V. J. (1996) Eur. J. Biochem. 236, 200–206). An early event in LPS signaling in hemocytes involves protein tyrosine phosphorylation (Charalambidis N. D., Zervas C. G., Lambropoulou M...

Injection of Serratia marcescens into the blood (hemolymph) of the silkworm, Bombyx mori, induced the activation of c-Jun NH(2)-terminal kinase (JNK), followed by caspase activation and apoptosis of blood cells (hemocytes). This process impaired the innate immune response in which pathogen cell wall components, such as glucan, stimulate hemocytes, leading to the activation of insect cytokine pa...

Injection of a culture supernatant of Serratia marcescens into the bloodstream of the silkworm Bombyx mori increased the number of freely circulating immunosurveillance cells (hemocytes). Using a bioassay with live silkworms, serralysin metalloprotease was purified from the culture supernatant and identified as the factor responsible for this activity. Serralysin inhibited the in vitro attachme...

Insect hemocytes have been the focus of researchers for decades (e.g., Jones, 1962; Ravindranath, 1978; Hall, 1983; Ribeiro & Brehelin, 2006). Most research has sought to increase our understanding of what factors influence hemocytes numbers, especially in response to various stressors (e.g., Silva et al., 2002; Andrade et al., 2003; Mochiah et al., 2003). Moreover, the recent increase in quest...

During a study of Rickettsiales-like organisms (RLO) in Pecten maximus gill, histological observation of free RLO in hemolymph led us to consider interactions between the pathogen and the hemocytes. Firstly, the production of oxygen radicals by hemocytes was established using a luminolenhanced chemiluminescence method with zymosan as stimulant. The effects of several inh~bitors of oxidative met...