An in vitro system to investigate the ability of macrophages recognize and ingest senescent polymorphonuclear neutrophils has been used that uses chromium-labeled staining for myeloperoxidase (MPO). Human monocyte-derived obtained from cultures were able "aged" but not freshly isolated 51Cr-labeled human them. Freshly monocytes did exhibit this property. Because aged greater than 95% viable, death appear be a prerequisite recognition ingestion. Serum was required aging neutrophils, when...

Enhancement of phagocytosis by serum from patients with sickle-cell disease was studied in an attempt to define further the opsonin deficiency present disorder and its role increased susceptibility these infection. Serums 28 promoted pneumococci normally if bacteria had previously been sensitized excess antibody, but a emerged when amount antibody added system decreased. The abnormality could not be attributed or complement components. However, under conditions that prevented activation C1...

The binding of the iC3b receptor (CR3) to unopsonized zymosan was shown result from CR3 attachment cell wall beta-glucans. A specificity neutrophil responses for beta-glucan first suggested by a comparison yeast (Saccharomyces cerevisiae) components stimulation superoxide burst. Neutrophils responded poorly heat-killed yeast, but gave increasingly better polysaccharides devoid proteins (zymosan) and nearly pure particles derived zymosan. Zymosan triggered burst that 29% as great stimulated...

The development of Fc and C3 receptor function was evaluated during differentiation human peripheral blood monocytes into macrophages in an vitro culture system. At the time isolation, formed rosettes with C3-coated erythrocytes (EIgMC) but did nt internalize them, whereas IgG-coated (EIgG) were both bound ingested. During first 24 hr culture, IgG-mediated phagocytosis C3-mediated rosette formation declined. After 7 days differentiation, monocyte-derived capable ingesting 2 to 4 times as...

Abstract In previous studies of the role IgG and C3b in opsonization, has not been present on target particle complete absence other serum proteins. We have developed a system which alone is particle, using trypsin cleavage purified C3. Sheep erythrocytes (E) coated with trypsin-generated (ETC3b) efficiently bound to but were ingested by human neutrophils. Specificity binding was demonstrated inhibition rosette formation fluid phase C3 or C3b, decrease rosettes after treatment ETC3b...

U937 is a human-derived lymphoma cell line that has monoblastic properties and high-affinity receptors for 1 alpha,-dihydroxyvitamin D3. Incubation of these cells with the vitamin D metabolite at 10 nM 5 days produced marked stimulation in adherence ingestion Staphylococcus aureus (645% control) C3b receptor (CR1) expression (292% slight increase hexose monophosphate shunt activity without changing growth rates or Fc fragment expression. The changes cellular association S. CR1 were detected...

Abstract Polymorphonuclear neutrophils (PMN) kill Cryptococcus neoformans (Cn) by oxidative mechanisms, but the roles of various reactive oxygen intermediates (ROIs) are not known. We used a mannitol low-producing Cn mutant (Cn MLP) and its wild-type parent H99) to examine role ROIs distal H2O2 in PMN killing determine whether produced protects fungus against ROIs. At PMN:Cn cell ratios 1:1, 10:1, 100:1, killed significantly more MLP than H99 cells after 2 4 h (p less 0.05). Superoxide...

Abstract Histoplasma capsulatum (Hc), is a facultative intracellular fungus that binds to CD11/CD18 receptors on macrophages (Mφ). To identify the ligand(s) Hc yeasts recognized by Mφ, purified human complement receptor type 3 (CR3, CD11b/CD18) was used probe Far Western blot of detergent extract cell wall and membrane. CR3 single 60-kDa protein, which identified as heat shock protein 60 (hsp60). Biotinylation viable yeasts, followed precipitation with streptavidin-coated beads, blotting...

Phagocytosis of Histoplasma capsulatum (Hc) yeasts and microconidia by human macrophages (M phi) was quantified a fluorescence quenching technique. unopsonized Hc monocyte-derived M phi alveolar (AM) rapid. After 60 min, 79% cultured 59% AM had ingested an average 9.8 11 yeasts/M phi, respectively. In contrast, only 26% monocytes 4.5 yeasts/cell after min. equivalent. Monoclonal antibodies specific for the alpha-chains beta-chain CD18 family adhesion receptors inhibited binding to AM. Thus,...

ABSTRACT Candida albicans is a component of the normal flora alimentary tract and also found on mucocutaneous membranes healthy host. leading cause invasive fungal disease in premature infants, diabetics, surgical patients, oropharyngeal AIDS patients. As induction cell-mediated immunity to critical importance host defense, we sought determine whether human dendritic cells (DC) could phagocytose degrade subsequently present antigens T cells. Immature DC obtained by culture monocytes presence...

We investigated the role of intracellular iron on capacity Histoplasma capsulatum (Hc) yeasts to multiply within human macrophages (Mphi). Coculture Hc-infected Mphi with chelator deferoxamine suppressed growth in a concentration-dependent manner. The effect was reversed by iron-saturated transferrin (holotransferrin) but not iron-free (apotransferrin). Chloroquine, which prevents release from raising endocytic and lysosomal pH, induced kill Hc. chloroquine nitriloacetate, an compound that...

Three genetically related strains of Blastomyces dermatitidis (Bd) yeasts that differ in their expression WI-1, an immunodominant cell wall Ag, were tested for capacity to bind human macrophages (M phi) the absence serum. These included American Type Culture Collection (ATCC, Rockville, MD) ATCC 26199, which is virulent mice; attenuated mutant strain 60915, expresses 2.5-fold more WI-1 than 26199; and avirulent strain, 60916, has sixfold 26199. Attachment both M phi was rapid maximum after...

Endoplasmic reticulum (ER) stress is a condition in which the protein folding capacity of ER becomes overwhelmed by an increased demand for secretion or exposure to compounds that disrupt homeostasis. In yeast and other fungi, accumulation unfolded proteins detected ER-transmembrane sensor IreA/Ire1, responds cleaving intron from downstream cytoplasmic mRNA HacA/Hac1, allowing translation transcription factor coordinates series adaptive responses are collectively known as response (UPR)....

We investigated the requirement for cellular cytoskeleton in CR- and FcR-mediated phagocytosis by human monocyte-derived macrophages (M phi). Inhibition of actin microfilament (MF) assembly stability cytochalasins B D completely inhibited M phi sheep E coated with C3b (EC3b), iC3b (EC3bi), IgG (EIgG) via CR1, CR3, FcR, respectively. Ligand-binding to either CR or FcR was not effected cytochalasins. Nocodazole (NOC), which prevents microtubule (MT) polymerization, taxol, causes random...

Histoplasma capsulatum (Hc) maintains a phagosomal pH of about 6.5. This strategy allows Hc to obtain iron from transferrin, and minimize the activity macrophage (Mo) lysosomal hydrolases. To determine mechanism regulation, we evaluated function vacuolar ATPase (V-ATPase) in RAW264.7 Mo infected with yeast or nonpathogenic Saccharomyces cerevisae (Sc). Incubation Hc-infected bafilomycin, an inhibitor V-ATPase, did not affect intracellular growth Hc, nor it intraphagosomal pH. In contrast,...

Histoplasma capsulatum (Hc) is a facultative, intracellular parasite of world-wide importance. As the induction cell-mediated immunity to Hc critical importance in host defense, we sought determine whether dendritic cells (DC) could function as primary APC for this pathogenic fungus. DC obtained by culture human monocytes presence GM-CSF and IL-4 phagocytosed yeasts time-dependent manner. Upon ingestion, growth within was completely inhibited compared with rapid macrophages. Electron...

To explore the role of neutrophil phagocytosis in host defense against Bordetella pertussis, bacteria were labeled extrinsically with fluorescein isothiocyanate (FITC) or genetically green fluorescent protein (GFP) and incubated adherent human neutrophils presence absence heat-inactivated immune serum. In antibodies, FITC-labeled located primarily on surface few ingested. However, after opsonization, about seven times more intracellularly, indicating that antibodies promoted phagocytosis....

Recombinant cytokines and colony-stimulating factors (CSFs) were tested for their abilities to activate human monocytes/macrophages (M phi) inhibit the intracellular growth of or kill Histoplasma capsulatum yeasts. None CSFs combinations activated M phi fungistatic activity when they added monolayers concurrently with In contrast, culture monocytes 7 days in presence interleukin 3, granulocyte-M CSF, CSF stimulated (but not fungicidal) against H. yeasts a concentration-dependent manner....

Eight cases of severe mucosal candidiasis in patients with AIDS who were taking fluconazole at a dosage 400–800 mg/d are described. Candida albicans alone or conjunction Torulopsis glabrata stellatoidea was isolated from each patient. In vitro susceptibility testing demonstrated resistance to all eight cases. All tested isolates susceptible amphotericin B, and six itraconazole. individuals severely immunocompromised (CD4 lymphocyte counts: mean, 15/mm3; range, 6–39/mm3) had been receiving...

In inflammation monocytes emigrate from the peripheral circulation into an extravascular area rich in extracellular matrix proteins. this milieu, phagocytes ingest and kill invading pathogens. present studies, we found that adhered to type I collagen gels phagocytized 2.5-12-fold more opsonized Escherichia coli, Staphylococcus aureus, Streptococcus pyogenes, pneumoniae than plastic-adherent monocytes. The rate of phagocytosis number bacteria ingested by collagen-adherent was equal to, or...

CONGENITAL deficiency of the second component complement (C2) has been reported frequently in association with collagen-vascular diseases.1 , 2 Most patients this disorder have not had serious infections.1 3 In cases which infections described, their pattern like that sometimes seen persons without a demonstrable defect immune system,3 4 5 6 7 8 making it difficult to relate certainty C2 and infection. two unrelated C2-deficient children described below, each having three episodes...

Histoplasma capsulatum is a dimorphic fungal pathogen that survives and replicates within macrophages (Mφ). Studies in human murine Mφ demonstrate the intracellular growth of H. yeasts exquisitely sensitive to availability iron. As produces hydroxamate siderophores, we sought determine if siderophores were required for survival Mφ, model pulmonary histoplasmosis. The expression SID1 (coding L-ornithine-N5-monooxygenase) was silenced by RNA interference (RNAi) strain G217B, abolished gene...