THE ENHANCEMENT OF BACTERIAL PHAGOCYTOSIS BY SERUM

The role of serum factors in the phagocytosis of pneumococci was studied employing a spectrophotometric assay which measures reduced nitro blue tetrazolium (NBT) dye. Dye reduction occurs within the phagocyte shortly after bacterial ingestion as measured by the phagocytic index technique and by the uptake of 125I-pneumococci. Bacteria prepared with γG antibody were not phagocytosed unless a small volume of fresh normal serum was added. Using fresh sera deficient in single complement components, it was demonstrated that the first four components are necessary for optimal bacterial phagocytosis. When highly purified complement components were added to the antibody-coated pneumococci, enhancement of phagocytosis was achieved only with the sequential addition of C1, C4, C2, and C3. Evidence has been presented that human C3 bound to an immune complex exhibits peptidase activity and that this activity is essential for phagocytosis. A heat-labile, dialyzable serum cofactor which enhances C3 peptidase activity enhanced the phagocytosis of pneumococci prepared with purified complement components. A second phagocytosis-promoting cofactor, which is not a complement component, was found to be a heat-labile, 5–6S, beta pseudoglobulin. This protein may stabilize C3 peptidase activity or inhibit enzymatic inactivation of C3.

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Intracellular Survival of Leishmania major in Neutrophil Granulocytes after Uptake in the Absence of Heat-Labile Serum Factors

Infection and Immunity ◽

10.1128/iai.70.2.826-835.2002 ◽

2002 ◽

Vol 70 (2) ◽

pp. 826-835 ◽

Cited By ~ 107

Author(s):

Helmut Laufs ◽

Kerstin Müller ◽

Jens Fleischer ◽

Norbert Reiling ◽

Nicole Jahnke ◽

...

Keyword(s):

Leishmania Major ◽

Intracellular Survival ◽

Host Cells ◽

Polymorphonuclear Neutrophil ◽

Heat Inactivation ◽

Neutrophil Granulocytes ◽

Complement Components ◽

Serum Factors

ABSTRACT The role of polymorphonuclear neutrophil granulocytes (PMN) in defense against the intracellular parasite Leishmania is poorly understood. In the present study, the interaction of human PMN with Leishmania major promastigotes was investigated in vitro. In the presence of fresh human serum, about 50% of PMN phagocytosed the parasites within 10 min and the parasite uptake led to PMN activation, resulting in the killing of most ingested parasites. Heat inactivation of the serum markedly reduced the rate of early parasite phagocytosis, suggesting a role of complement components in the early uptake of Leishmania. However, over 50% of PMN were able to ingest parasites in the presence of heat-inactivated serum if the coincubation was extended to 3 h. After 3 h, 10% of the PMN were found to internalize Leishmania even under serum-free conditions. These findings indicate that PMN possess mechanisms for both opsonin/complement-dependent and -independent uptake of Leishmania. Both pathways of uptake could be partially blocked by anti-CR3 antibody. Mannan-binding lectin was found not to be involved in this process. When phagocytosed in the absence of opsonin, the majority of Leishmania parasites survived intracellularly in PMN for at least 1 day. These data suggest a dual role of PMN in the early response to L. major infection. On the one hand, PMN can rapidly eliminate the intracellular parasites, and on the other hand, Leishmania can survive intracellularly in PMN. These data, together with the finding that intact parasites were seen in PMN isolated from the skin of infected mice, suggest that PMN can serve as host cells for the intracellular survival of Leishmania within the first hours or days after infection.

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Hepcidin Overproduction Mediates the Anemia of Multiple Myeloma.

Blood ◽

10.1182/blood.v108.11.516.516 ◽

2006 ◽

Vol 108 (11) ◽

pp. 516-516

Author(s):

Sanjai Sharma ◽

Elizabeta Nemeth ◽

Yi-Hsiang Chen ◽

Alissa Huston ◽

G.D. Roodman ◽

...

Keyword(s):

Multiple Myeloma ◽

Inverse Correlation ◽

Normal Serum ◽

Serum Factors ◽

Hepcidin Level ◽

Hepcidin Expression ◽

Reactive Protein ◽

Enhanced Expression

Abstract Hepcidin is a liver-produced protein that has been implicated in the anemia of chronic inflammatory/infectious disease. Hepcidin expression is stimulated during infection/inflammation and, by downregulating the iron exporter ferroportin, hepcidin prevents release of iron from macrophages and enterocytes. This results in a decrease in delivery of iron to maturing erythrocytes and significant anemia. Since IL-6 is the major cytokine upregulating hepcidin expression during inflammation/infection and, since high levels of IL-6 are often present in multiple myeloma (MM), we initiated the current study examining a role of hepcidin in the anemia of MM. Pretreatment urinary hepcidin levels were determined in 44 patients with stage III MM. The mean level of hepcidin (191ng/mg of creatinine) was significantly higher than normal controls (64.5ng/mg of creatinine). In contrast, patients with MGUS did not demonstrate elevated hepcidin levels. In the subset of MM patients without renal insufficiency (n=27) a marked inverse correlation was seen between hemoglobin level at diagnosis and hepcidin level (r= −0.46, p=0.014). This correlation is even more impressive because anemia in general (when not due to hepcidin overexpression) results in a decrease in hepcidin levels. These data strongly supported hepcidin upregulation as a major cause of anemia of MM. The hepcidin level also correlated with serum ferritin levels (n=28, r=0.37, p=0.048). A role for IL-6 in hepcidin upregulation was suggested by a significant correlation between hepcidin levels and C-reactive protein, an IL-6 targeted gene (n=28, r= 0.57, p=0.0012). However a correlation between hepcidin and serum IL-6 levels just missed significance (n=27, r= 0.36, p= 0.0599). Furthermore, real time PCR in vitro studies also suggested that IL-6 played a role but could not completely account for all cases of hepcidin upregulation. As compared to normal serum, sera from six MM patients (with known elevated hepcidin levels) significantly induced hepcidin RNA in a liver cell line, Hep3B. In the patients with co-existing high IL-6 levels, the serum-induced hepcidin RNA was prevented by anti-IL-6 and anti-IL6 receptor antibodies. However, in the patients with lower IL-6 levels, these blocking antibodies were unable to prevent sera-induced hepcidin RNA. Additional studies on myeloma cells isolated from marrow of a patient with high hepcidin level demonstrated an absence of hepcidin RNA in the resting or IL-6 stimulated state, indicating that the MM cells themselves do not participate in the increased production of hepcidin. These data strongly support the notion that enhanced expression of hepcidin is an important cause of the anemia of MM and suggest a role of IL-6 and other, yet to be identified, serum factors in the hepcidin upregulation.

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The Role of High Fat Diets and Liver Peptidase Activity in the Development of Obesity and Insulin Resistance in Wistar Rats

Nutrients ◽

10.3390/nu12030636 ◽

2020 ◽

Vol 12 (3) ◽

pp. 636

Author(s):

Germán Domínguez-Vías ◽

Ana Belén Segarra ◽

Manuel Ramírez-Sánchez ◽

Isabel Prieto

Keyword(s):

Glucose Metabolism ◽

Wistar Rats ◽

Metabolic Disorders ◽

Peptidase Activity ◽

High Fat ◽

Β Cell ◽

High Fat Diets ◽

Glutamyl Transferase ◽

Fat Diets

High-fat diets (HFD) have been widely associated with an increased risk of metabolic disorders and overweight. However, a high intake of sources that are rich in monounsaturated fatty acids has been suggested as a dietary agent that is able to positively influence energy metabolism and vascular function. The main objective of this study was to analyze the role of dietary fats on hepatic peptidases activities and metabolic disorders. Three diets: standard (S), HFD supplemented with virgin olive oil (VOO), and HFD supplemented with butter plus cholesterol (Bch), were administered over six months to male Wistar rats. Plasma and liver samples were collected for clinical biochemistry and aminopeptidase activities (AP) analysis. The expression of inducible nitric oxide synthase (iNOS) was also determined by Western blot in liver samples. The diet supplement with VOO did not induce obesity, in contrast to the Bch group. Though the VOO diet increased the time that was needed to return to the basal levels of plasma glucose, the fasting insulin/glucose ratio and HOMA2-%B index (a homeostasis model index of insulin secretion and valuation of β-cell usefulness (% β-cell secretion)) were improved. An increase of hepatic membrane-bound dipeptidyl-peptidase 4 (DPP4) activity was found only in VOO rats, even if no differences in fasting plasma glucagon-like peptide 1 (GLP-1) were obtained. Both HFDs induced changes in hepatic pyroglutamyl-AP in the soluble fraction, but only the Bch diet increased the soluble tyrosyl-AP. Angiotensinase activities that are implicated in the metabolism of angiotensin II (AngII) to AngIV increased in the VOO diet, which was in agreement with the higher activity of insulin-regulated-AP (IRAP) in this group. Otherwise, the diet that was enriched with butter increased soluble gamma-glutamyl transferase (GGT) and Leucyl-AP, iNOS expression in the liver, and plasma NO. In summary, VOO increased the hepatic activity of AP that were related to glucose metabolism (DPP4, angiotensinases, and IRAP). However, the Bch diet increased activities that are implicated in the control of food intake (Tyrosine-AP), the index of hepatic damage (Leucine-AP and GGT), and the expression of hepatic iNOS and plasma NO. Taken together, these results support that the source of fat in the diet affects several peptidases activities in the liver, which could be related to alterations in feeding behavior and glucose metabolism.

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The Role of Coagulation and Complement Factors for Mast Cell Activation in the Pathogenesis of Chronic Spontaneous Urticaria

Cells ◽

10.3390/cells10071759 ◽

2021 ◽

Vol 10 (7) ◽

pp. 1759

Author(s):

Yuhki Yanase ◽

Shunsuke Takahagi ◽

Koichiro Ozawa ◽

Michihiro Hide

Keyword(s):

Mast Cells ◽

Cell Activation ◽

Coagulation Factors ◽

Chronic Spontaneous Urticaria ◽

Mast Cell Activation ◽

Coagulation Cascade ◽

Edema Formation ◽

Complement Components ◽

Complement Factors

Chronic spontaneous urticaria (CSU) is a common skin disorder characterized by an almost daily recurrence of wheal and flare with itch for more than 6 weeks, in association with the release of stored inflammatory mediators, such as histamine, from skin mast cells and/or peripheral basophils. The involvement of the extrinsic coagulation cascade triggered by tissue factor (TF) and complement factors, such as C3a and C5a, has been implied in the pathogenesis of CSU. However, it has been unclear how the TF-triggered coagulation pathway and complement factors induce the activation of skin mast cells and peripheral basophils in patients with CSU. In this review, we focus on the role of vascular endothelial cells, leukocytes, extrinsic coagulation factors and complement components on TF-induced activation of skin mast cells and peripheral basophils followed by the edema formation clinically recognized as urticaria. These findings suggest that medications targeting activated coagulation factors and/or complement components may represent new and effective treatments for patients with severe and refractory CSU.

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C3 Promotes Clearance of Klebsiella pneumoniae by A549 Epithelial Cells

Infection and Immunity ◽

10.1128/iai.72.3.1767-1774.2004 ◽

2004 ◽

Vol 72 (3) ◽

pp. 1767-1774 ◽

Cited By ~ 26

Author(s):

Beatriz de Astorza ◽

Guadalupe Cortés ◽

Catalina Crespí ◽

Carles Saus ◽

José María Rojo ◽

...

Keyword(s):

Epithelial Cells ◽

Klebsiella Pneumoniae ◽

Alveolar Epithelial Cells ◽

Clinical Isolates ◽

Complement Components ◽

Innate Defense ◽

Alveolar Epithelial

ABSTRACT The airway epithelium represents a primary site for contact between microbes and their hosts. To assess the role of complement in this event, we studied the interaction between the A549 cell line derived from human alveolar epithelial cells and a major nosocomial pathogen, Klebsiella pneumoniae, in the presence of serum. In vitro, we found that C3 opsonization of poorly encapsulated K. pneumoniae clinical isolates and an unencapsulated mutant enhanced dramatically bacterial internalization by A549 epithelial cells compared to highly encapsulated clinical isolates. Local complement components (either present in the human bronchoalveolar lavage or produced by A549 epithelial cells) were sufficient to opsonize K. pneumoniae. CD46 could competitively inhibit the internalization of K. pneumoniae by the epithelial cells, suggesting that CD46 is a receptor for the binding of complement-opsonized K. pneumoniae to these cells. We observed that poorly encapsulated strains appeared into the alveolar epithelial cells in vivo but that (by contrast) they were completely avirulent in a mouse model of pneumonia compared to the highly encapsulated strains. Our results show that bacterial opsonization by complement enhances the internalization of the avirulent microorganisms by nonphagocytic cells such as A549 epithelial cells and allows an efficient innate defense.

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IDIOPATHIC HYPERCALCEMIA

PEDIATRICS ◽

10.1542/peds.24.2.258 ◽

1959 ◽

Vol 24 (2) ◽

pp. 258-269

Author(s):

David W. Smith ◽

Robert M. Blizzard ◽

Harold E. Harrison

Keyword(s):

Vitamin D ◽

Serum Calcium ◽

Normal Serum ◽

Early Infancy ◽

Serum Assay ◽

Supplemental Vitamin ◽

Normal Serum Calcium

A case of idiopathic hypercalcemia present from early infancy and diagnosed at 5 years of age is reported in which the serum assay of vitamin D indicated elevated levels. After discontinuation of supplemental vitamin D and a diet low in calcium the concentrations of calcium and vitamin D in the serum gradually returned to normal over a period of 18 months. Roentgenograms of the bones showed evidence of demineralization rather than increased density as reported in other cases of "idiopathic" hypercalcemia. During a subsequent 2-year follow-up the patient has maintained a normal serum calcium. The etiology is discussed with particular reference to the role of vitamin D in this case

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Insulin treatment fails to abolish the teratogenic potential of serum from diabetic rats

Acta Endocrinologica ◽

10.1530/eje.0.1340459 ◽

1996 ◽

Vol 134 (4) ◽

pp. 459-466 ◽

Cited By ~ 18

Author(s):

Parri Wentzel ◽

Ulf J Eriksson

Keyword(s):

Glucose Concentration ◽

Insulin Treatment ◽

Ketone Bodies ◽

Diabetic Rats ◽

Normal Serum ◽

Serum Factors ◽

Crown Rump Length ◽

Increased Risk ◽

Control Serum ◽

Teratogenic Potential

Wentzel P, Eriksson UJ. Insulin treatment fails to abolish the teratogenic potential of serum from diabetic rats. Eur J Endocrinol 1996;134:459–66. ISSN 0804–4643 Maternal diabetes during pregnancy constitutes an increased risk for congenital malformations in the offspring. Previous studies have identified several serum components with teratogenic activity, e.g. glucose and β-hydroxybutyrate, but have also suggested that the teratogenic influence of the diabetic environment on the developing embryo is multifactorial and may depend upon changed concentrations of several maternal metabolites. In the present investigation we aimed to assess the teratological impact of small, concomitant alterations in a series of metabolites, particularly those not previously identified as teratogens. We thus investigated the influence of a mild diabetic environment by culturing gestational day-9 rat embryos in serum from insulin-treated diabetic rats for 48 h in vitro, and compared the embryonic outcome with that obtained after culture in normal serum and in serum from manifestly diabetic rats without insulin treatment. The glucose concentration was adjusted to 10 or 30 mmol/l in the cultures, and the embryos were evaluated with respect to crown–rump length, protein and DNA content, number of somites and malformation score (comparing major, minor or no malformations). We found that increased glucose levels caused embryonic maldevelopment in both normal and diabetic serum, and that despite normalization of the diabetic state, the serum from the insulin-treated diabetic rats caused more growth retardation than the nondiabetic control serum. The normalized diabetic serum was also more teratogenic than the normal serum at the low glucose concentration, whereas the serum from the manifestly diabetic rats tended to cause more dysmorphogenesis at 30 mmol/l glucose than both the normal and normalized diabetic serum. The results suggest that the teratogenicity of maternal serum in diabetic pregnancy is not mediated exclusively by increased concentrations of glucose and ketone bodies. The efforts to diminish the teratogenic effects of a diabetic environment should therefore include normalization of a multitude of serum factors, including glucose and ketone bodies. Parri Wentzel, Department of Medical Cell Biology, University of Uppsala, Biomedicum, PO Box 571, S-751 23 Uppsala, Sweden

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Some Comments on the Role of Blocking Serum Factors in Tolerance to Allografts

Cellular Antigens ◽

10.1007/978-1-4612-9843-4_28 ◽

1972 ◽

pp. 314-316

Author(s):

Ingegerd Hellström ◽

Karl Erik Hellström

Keyword(s):

Serum Factors

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Saccharomyces cerevisiae enhanced the growth, immune and antioxidative responses of European seabass (Dicentrarchus labrax)

Annals of Animal Science ◽

10.2478/aoas-2021-0012 ◽

2021 ◽

Vol 0 (0) ◽

Author(s):

Mahmoud A.O. Dawood ◽

Marwa F. Abd El-Kader ◽

Mona A. Farid ◽

Mohamed F. Abd-Elghany ◽

Mohamed Alkafafy ◽

...

Keyword(s):

Saccharomyces Cerevisiae ◽

Specific Growth ◽

Body Weight Gain ◽

Dicentrarchus Labrax ◽

Basal Diet ◽

Phagocytic Index ◽

Final Body Weight ◽

Antioxidative Responses ◽

European Seabass

Abstract The concept of probiotics is widely applied in the field of aquaculture for their beneficial and friendly influences. In this sense, the role of Saccharomyces cerevisiae on the growth, immune and antioxidative responses of European seabass was tested in this study. Fish were distributed in 3 groups (triplicates) with ten fish in each replicate and fed 0, 1, and 2 g/kg of S. cerevisiae (15×109 CFU/g) for 90 days. Fish fed S. cerevisiae showed higher final body, weight gain, and specific growth rate as well as lower FCR than fish fed the basal diet (P<0.05). The RBCs, WBCs, Hb, and PCV values were increased in fish fed dietary S. cerevisiae when compared to the control (P<0.05). The blood total protein, albumin, and globulin were higher in fish fed S. cerevisiae than the control (P<0.05). Fish fed dietary S. cerevisiae had enhanced phagocytic index, phagocytic, and lysozyme activity comparing the control. In a similar sense, the antioxidative enzymes (SOD, GPx, and CAT) were higher in fish fed S. cerevisiae than the control (P<0.05). However, the level of MDA was lowered (P<0.05) by S. cerevisiae in European seabass. Gene expression of IL-8, IL-1β, GH, and IGF-1 was upregulated and HSP70 was downregulated by S. cerevisiae (P<0.05). It can be concluded that European seabass fed S. cerevisiae at 1-2 g/kg (15×109 CFU/g) diet had markedly enhanced growth, haemato-biochemical, and immune performances.

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Dendritic cells play no significant role in the laser-induced choroidal neovascularization model

Scientific Reports ◽

10.1038/s41598-021-96704-x ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Steven Droho ◽

Harris Perlman ◽

Jeremy A. Lavine

Keyword(s):

Dendritic Cells ◽

Steady State ◽

Choroidal Neovascularization ◽

Significant Role ◽

Age Related Macular Degeneration ◽

Complement Components ◽

Innate And Adaptive Immunity ◽

Laser Injury ◽

Age Related

AbstractAge-related macular degeneration (AMD) is genetically associated with complement. Dendritic cells (DCs) play key roles during innate and adaptive immunity, and express complement components and their receptors. We investigated ocular DC heterogeneity and the role of DCs in the laser-induced choroidal neovascularization (CNV) model. In order to determine the function of DCs, we used two models of DC deficiency: the Flt3−/− and Flt3l−/− mouse. We identified three types of ocular DCs: plasmacytoid DC, classical DC-1, and classical DC-2. At steady-state, classical DCs were found in the iris and choroid but were not detectable in the retina. Plasmacytoid DCs existed at very low levels in iris, choroid, and retina. After laser injury, the number of each DC subset was up-regulated in the choroid and retina. In Flt3−/− mice, we found reduced numbers of classical DCs at steady-state, but each DC subset equally increased after laser injury between wildtype and Flt3−/− mice. In Flt3l−/− mice, each DC subsets was severely reduced after laser injury. Neither Flt3−/− or Flt3l−/− mice demonstrated reduced CNV area compared to wildtype mice. DCs do not play any significant role during the laser-induced CNV model of neovascular AMD.

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