Diverse receptors, including Fc receptors and 2 integrins (complement receptor-3 [CR3], CD11b/CD18), have been implicated in phagocytosis, but their distinct roles and interactions with other receptors in particle engulfment are not well defined. CD44, a transmembrane adhesion molecule involved in binding and metabolism of hyaluronan, may have additional functions in regulation of inflammation ...

Mono-Mac-6 (MM6) human monocytes ingest IgG-opsonized particles better than other human cell lines. We compared the phagocytic signaling pathway in MM6 with human monocytes. MM6 expressed FcgammaRI at levels similar to monocytes, whereas FcRgammaII expression was approximately double. MM6 ingested IgG-opsonized erythrocytes (EIgG) in a calcium-independent manner. Incubation of MM6 with bromoeno...

Thirteen chemotherapeutic agents were tested for modulatory activity on phagocytosis by human granulocytes and monocytes. Phagocytosis, phagocytic index, and intracellular bactericidal activity were assessed using Staphylococcus aureus, smooth strain of Escherichia coli, and latex particles. Modulation of phagocytic activity depended on the type of particle used and the presence of serum in the...

Mucoid Pseudomonas aeruginosa colonizes and infects the respiratory tract of most older patients with cystic fibrosis. These bacteria resist both opsonin-dependent and -independent phagocytosis by human polymorphonuclear leukocytes and monocyte-derived macrophages. Resistance to phagocytosis is thought to be mediated in part by the mucoid exopolysaccharide associated with the bacterial surface....

Under a variety of pathologic conditions, glial cells of the retina are capable of phagocytosis. Although phagocytosis may play a role in retinal pathobiology, the regulation of the phagocytic activity of retinal glial cells is poorly understood. We used a culture system to study phagocytosis by human retinal glial cells. The cultured cells were obtained from adult postmortem eyes and were immu...

Phagocytosis is a fundamental process of cells to capture and ingest foreign particles. Small unicellular organisms such as free-living amoeba use this process to acquire food. In pluricellular organisms, phagocytosis is a universal phenomenon that all cells are able to perform (including epithelial, endothelial, fibroblasts, etc.), but some specialized cells (such as neutrophils and macrophage...

Phagocytosis of Ab-coated pathogens is mediated through FcγRs, which activate intracellular signaling pathways to drive actin cytoskeletal rearrangements. Abl and Arg define a family of nonreceptor tyrosine kinases that regulate actin-dependent processes in a variety of cell types, including those important in the adaptive immune response. Using pharmacological inhibition as well as dominant ne...

Pseudomonas aeruginosa causes severe respiratory tract infections in patients with cystic fibrosis (CF). We have been examining nonopsonic phagocytosis of P. aeruginosa by macrophages. To study the P. aeruginosa-macrophage interaction at the molecular level, we have constructed a transposon Tn5G bank in a clinical isolate of P. aeruginosa (strain 4020) and identified mutants resistant to nonops...

Microglia are the resident brain macrophages and they have been traditionally studied as orchestrators of the brain inflammatory response during infections and disease. In addition, microglia has a more benign, less explored role as the brain professional phagocytes. Phagocytosis is a term coined from the Greek to describe the receptor-mediated engulfment and degradation of dead cells and micro...

Extracellular and bacterial factors that influence the phagocytosis and killing of staphylococci by human polymorphonuclear leukocytes have been studied. Staphylococcus epidermidis strains were, in general, more rapidly phagocytized than were S. aureus strains. However, two strains of S. epidermidis had a very slow rate of ingestion. Although the rate of phagocytosis of S. aureus Wood 46 was gr...