scholarly journals Complement Interaction with Trypanosomatid Promastigotes in Normal Human Serum

2002 ◽  
Vol 195 (4) ◽  
pp. 451-459 ◽  
Author(s):  
Mercedes Domínguez ◽  
Inmaculada Moreno ◽  
Margarita López-Trascasa ◽  
Alfredo Toraño
Keyword(s):  
Human Serum ◽  
Binding Capacity ◽  
Normal Human Serum ◽  
Leishmania Infection ◽  
Classical Pathway ◽  
Classical Complement Pathway ◽  
Ethylenediaminetetracetic Acid ◽  
Human Sera ◽  
Normal Human

In normal human serum (NHS), axenic promastigotes of Crithidia, Phytomonas, and Leishmania trigger complement activation, and from 1.2 to 1.8 × 105 C3 molecules are deposited per promastigote within 2.5 min. In Leishmania, promastigote C3 binding capacity remains constant during in vitro metacyclogenesis. C3 deposition on promastigotes activated through the classical complement pathway reaches a 50% maximum after ∼50 s, and represents >85% of total C3 bound. In C1q- and C2-deficient human sera, promastigotes cannot activate the classical pathway (CP) unless purified C1q or C2 factors, respectively, are supplemented, demonstrating a requirement for CP factor in promastigote C3 opsonization. NHS depleted of natural anti-Leishmania antibodies cannot trigger promastigote CP activation, but IgM addition restores C3 binding. Furthermore, Leishmania binds natural antibodies in ethylenediaminetetracetic acid (EDTA)-treated NHS; after EDTA removal, promastigote-bound IgM triggers C3 deposition in natural antibody-depleted NHS. Serum collectins and pentraxins thus do not participate significantly in NHS promastigote C3 opsonization. Real-time kinetic analysis of promastigote CP-mediated lysis indicates that between 85–95% of parasites are killed within 2.5 min of serum contact. These data indicate that successful Leishmania infection in man must immediately follow promastigote transmission, and that Leishmania evasion strategies are shaped by the selective pressure exerted by complement.

scholarly journals High doses of intravenous immunoglobulin do not affect the recognition phase of the classical complement pathway

Blood ◽  
1991 ◽  
Vol 78 (3) ◽  
pp. 700-702
Author(s):  
M Basta ◽  
LF Fries ◽  
MM Frank
Keyword(s):  
Human Serum ◽  
Intravenous Immunoglobulin ◽  
Normal Serum ◽  
Normal Human Serum ◽  
Complement Pathway ◽  
Classical Complement Pathway ◽  
Recognition Phase ◽  
Normal Human ◽  
Classical Complement

We have recently found that intravenous immunoglobulin (IVIg) prevents deposition of C3 and C4 fragments onto antibody sensitized erythrocytes. To find out if such an effect results from the blockade of the recognition phase of the classical complement cascade, we investigated the ability of human serum containing high concentrations of IVIg to deposit the recognition subunit of the first complement component (C1q) onto targets. Normal human serum supplemented in vitro with IVIg did not demonstrate reduced C1q binding to targets as determined by radiolabeled antihuman C1q antibody uptake. Similarly, methylamine-treated normal human serum to which IVIg was added was equally effective in terms of C1q binding as the same serum without IVIg. At increasing doses of sensitizing antibody, C1q uptake decreased proportionally; however, at all antibody dilution points C1q uptake was not significantly different in the serum with IVIg in comparison with normal serum. Serum from a patient treated with IVIg did not differ in its capacity to deposit C1q from the same patient's serum before therapy. Our data suggest that IVIg does not interfere with the recognition step of classical complement pathway. This is a US government work. There are no restrictions on its use.

scholarly journals High doses of intravenous immunoglobulin do not affect the recognition phase of the classical complement pathway

Blood ◽  
1991 ◽  
Vol 78 (3) ◽  
pp. 700-702 ◽  
Author(s):  
M Basta ◽  
LF Fries ◽  
MM Frank
Keyword(s):  
Human Serum ◽  
Intravenous Immunoglobulin ◽  
Normal Serum ◽  
Normal Human Serum ◽  
Complement Pathway ◽  
Classical Complement Pathway ◽  
Recognition Phase ◽  
Normal Human ◽  
Classical Complement

Abstract We have recently found that intravenous immunoglobulin (IVIg) prevents deposition of C3 and C4 fragments onto antibody sensitized erythrocytes. To find out if such an effect results from the blockade of the recognition phase of the classical complement cascade, we investigated the ability of human serum containing high concentrations of IVIg to deposit the recognition subunit of the first complement component (C1q) onto targets. Normal human serum supplemented in vitro with IVIg did not demonstrate reduced C1q binding to targets as determined by radiolabeled antihuman C1q antibody uptake. Similarly, methylamine-treated normal human serum to which IVIg was added was equally effective in terms of C1q binding as the same serum without IVIg. At increasing doses of sensitizing antibody, C1q uptake decreased proportionally; however, at all antibody dilution points C1q uptake was not significantly different in the serum with IVIg in comparison with normal serum. Serum from a patient treated with IVIg did not differ in its capacity to deposit C1q from the same patient's serum before therapy. Our data suggest that IVIg does not interfere with the recognition step of classical complement pathway. This is a US government work. There are no restrictions on its use.

State of iron(III) in normal human serum: low molecular weight and protein ligands besides transferrin

1970 ◽  
Vol 48 (12) ◽  
pp. 1339-1350 ◽  
Author(s):  
Bibudhendra Sarkar
Keyword(s):  
Molecular Weight ◽  
Human Serum ◽  
Binding Capacity ◽  
Normal Serum ◽  
Normal Human Serum ◽  
Void Volume ◽  
Antibody Concentration ◽  
Low Molecular Weight ◽  
Protein Ligands ◽  
Normal Human

A fraction of Fe(III) in normal human serum is bound to both low molecular weight as well as protein ligands besides transferrin. Citrate was shown to be the major Fe(III)-binding substance in the low molecular weight fraction. Amino acids, sugars, and organic acids, such as ascorbate, pyruvate, and lactate, showed very little or no binding to Fe(III) in normal serum. Iron(III)-binding proteins other than transferrin were shown to be present in normal serum when the native serum with [59Fe(III)] was fractionated by (NH4)2SO4 and Sephadex G-150. The presence of these proteins was observed when trace amounts of Fe(III) were added to the normal serum and when the iron-binding capacity was saturated with Fe(III) to 50% and 100%. These proteins were eluted in the void volume of Sephadex G-150 and none of them corresponded electrophoretically to transferrin. The results of the gel filtration of a mixture of [131I]-transferrin and the proteins eluted in the void volume of Sephadex G-150 were strongly in favor of the Fe(III)-proteins as being neither transferrin aggregates nor transferrin adducts with other proteins. Immunoelectrophoresis of the Sephadex G-150 void volume proteins on agar gel against the antibody to transferrin revealed the absence of transferrin. The presence of at least six proteins in this fraction was shown by immunoelectrophoresis. Positive precipitin reactions were obtained with the antibodies to α2-macroglobulin, γG-globulin, γA-globulin, and γM-globulin. At least two more proteins in this fraction remained unidentified. When the same fraction containing [59Fe(III)] was treated with the whole antisera and the precipitates were counted for radioactivity, a typical antigen-antibody reaction curve was obtained as the antibody concentration was increased. Similar experiments with this fraction and antibodies to α2-macroglobulin, γG-globulin, γA-globulin, and γM-globulin failed to show any significant radioactivity in the precipitate. Since this fraction did not contain any transferrin, it was concluded that there are proteins besides transferrin which can act as ligands for Fe(III) in normal blood plasma.

The Binding of Lithium Carmine to a2-Macroglobulin

1969 ◽  
Vol 24 (11) ◽  
pp. 1442-1447 ◽  
Author(s):  
J. J. Picard ◽  
J. F. Heremans
Keyword(s):  
Human Serum ◽  
Density Gradient ◽  
Protein Complex ◽  
Gel Filtration ◽  
Heavy Fraction ◽  
Normal Human Serum ◽  
Density Gradient Ultracentrifugation ◽  
Γ Globulins ◽  
Normal Human

The colloidal dye lithium carmine was added in vitro to normal human serum. Electrophoretic experiments showed that the dye was associated mainly with α2-globulins, small amounts with the albumin and only traces with the γ-globulins. The main complex was eluted with the macroglobulin peak obtained by gel filtration on Sephadex G-200 and sedimented in the heavy fraction on density gradient ultracentrifugation. The dye-protein complex could be precipitated with an antiserum specific for a2-macroglobulin. Gel filtration of a solution of pure a2-macroglobulin, to which lithium carmine was added, demonstrated that the dye was bound to this protein.

scholarly journals Human Serum Contains a Protease That Protects against Cytotoxic Activity of Bacillus anthracis Lethal Toxin In Vitro

2008 ◽  
Vol 15 (6) ◽  
pp. 970-973 ◽  
Author(s):  
David L. Goldman ◽  
WangYong Zeng ◽  
Johanna Rivera ◽  
Antonio Nakouzzi ◽  
Arturo Casadevall
Keyword(s):  
Heat Treatment ◽  
Bacillus Anthracis ◽  
Human Serum ◽  
Protective Antigen ◽  
Lethal Toxin ◽  
Protective Activity ◽  
Calcium Chelation ◽  
Human Sera ◽  
Normal Human

ABSTRACT The role of innate immunity in the host response to Bacillus anthracis is poorly understood. We found that normal human serum contains an antitoxin mechanism that is capable of protecting macrophages in vitro from B. anthracis lethal toxin-mediated killing. This protective activity was limited to defined amounts of toxin and was lost by heat treatment or serum dilution. Some person-to-person variation in the protective activity of serum was noted, especially with higher concentrations of lethal toxin. A similar protective activity was found in murine serum, though human serum consistently neutralized more toxin than did murine serum. The protective activities of both murine and human sera correlated with cleavage of the protective antigen into two fragments with approximate molecular sizes of 20 and 50 kDa that were recognized by the monoclonal antibodies 7.5G and 10F4, respectively. This pattern of fragmentation is consistent with cleavage at multiple sites, including the furin-susceptible site. Cleavage was abolished by heat treatment and calcium chelation. These findings highlight a potential role for serum proteases in protection against the lethal toxin of B. anthracis.

Stimulation by serum of aldosterone production from rat adrenal glomerulosa cells in vitro: relationships to K+, serotonin and angiotensin II

1981 ◽  
Vol 97 (2) ◽  
pp. 231-242 ◽  
Author(s):  
F. A. O. Mendelsohn ◽  
Christine D. Kachel
Keyword(s):  
Angiotensin Ii ◽  
Human Serum ◽  
Normal Subjects ◽  
Normal Human Serum ◽  
Rpmi Medium ◽  
High K ◽  
Aldosterone Production ◽  
Normal Human ◽  
Glomerulosa Cells

Abstract. Normal human serum markedly stimulated aldosterone production from rat adrenal glomerulosa cells incubated in Krebs Ringer bicarbonate medium (KRBGA). The effect was dose-related. In [K+] 3.6 mm KRBGA medium, serum stimulated aldosterone output to higher levels than those produced by maximal doses of serotonin (5 HT), angiotensin II (AII) or high [K+] (8.4 mm). Cells maximally stimulated by high [K+], 5 HT or AII in KRBGA medium were further stimulated by serum. The angiotensin analogue, [Sar1, Ala8]-AII abolished the effect of AII but not that of high [K+] or serum. Basal and ACTH-stimulated corticosterone outputs of rat fasciculata cells were not significantly affected by sera known to stimulate glomerulosa cells. Aldosterone stimulating activity of serum was dialysable and fully recovered in a serum ultrafiltrate. The serotonin blockers methysergide and metergoline abolished the aldosterone stimulating activity of serum but also depressed basal aldosterone output and methysergide reduced K+-stimulated output. Chymotrypsin digestion abolished the aldosterone stimulating activity of AII but not that of serotonin or serum. 5 HT concentration of sera was measured and found to be near the threshold for aldosterone stimulation. Sodium loading and depletion of 4 normal subjects did not consistently modify the aldosterone stimulating activity of their sera. In a supplemented medium (RPMI 1640), basal and K+-stimulated aldosterone outputs were higher than in KRBGA medium. Under these conditions serum stimulated aldosterone output in normal [K+] medium but only marginally in high [K+] medium. In RPMI medium, serum did not further stimulate cells maximally stimulated with serotonin. Serum appears to stimulate aldosterone production from glomerulsoa cells by two different mechanisms: One is probably due to a serotonin-like substance. A separate effect of serum, seen only in KRBGA medium, is to enhance aldosterone output of glomerulosa cells maximally stimulated by K+, 5 HT or AII.

scholarly journals The effect of normal human serum on the mouse trypanosome Trypanosoma musculi in vitro and in vivo

2018 ◽  
Vol 184 ◽  
pp. 115-120
Author(s):  
Xuan Zhang ◽  
Xiao-Kun Hong ◽  
Su-Jin Li ◽  
De-Hua Lai ◽  
Geoff Hide ◽  
...  
Keyword(s):  
Human Serum ◽  
Normal Human Serum ◽  
Normal Human

scholarly journals The UspA2 Protein of Moraxella catarrhalis Is Directly Involved in the Expression of Serum Resistance

2005 ◽  
Vol 73 (4) ◽  
pp. 2400-2410 ◽  
Author(s):  
Ahmed S. Attia ◽  
Eric R. Lafontaine ◽  
Jo L. Latimer ◽  
Christoph Aebi ◽  
George A. Syrogiannopoulos ◽  
...  
Keyword(s):  
Human Serum ◽  
Resistant Strain ◽  
Moraxella Catarrhalis ◽  
Normal Human Serum ◽  
Serum Resistance ◽  
Complement Pathway ◽  
Classical Complement Pathway ◽  
Amino Acid Region ◽  
Normal Human ◽  
Classical Complement

ABSTRACT Many strains of Moraxella catarrhalis are resistant to the bactericidal activity of normal human serum. Previous studies have shown that mutations involving the insertion of an antibiotic resistance cartridge into the M. catarrhalis uspA2 gene resulted in the conversion of a serum-resistant strain to a serum-sensitive phenotype. In the present study, the deletion of the entire uspA2 gene from the serum-resistant M. catarrhalis strain O35E resulted in a serum-sensitive phenotype and did not affect either the rate of growth or the lipooligosaccharide expression profile of this mutant. Inactivation of the classical complement pathway in normal human serum with Mg2+ and EGTA resulted in the survival of this uspA2 mutant. In contrast, blocking of the alternative complement pathway did not protect this uspA2 mutant from complement-mediated killing. To determine whether the UspA2 protein is directly involved in serum resistance, transformation and allelic exchange were used to replace the uspA2 gene in the serum-resistant strain O35E with the uspA2 gene from the serum-sensitive M. catarrhalis strain MC317. The resultant O35E transformant exhibited a serum-sensitive phenotype. Similarly, when the uspA2 gene from the serum-resistant strain O35E was used to replace the uspA2 gene in the serum-sensitive strain MC317, the MC317 transformant acquired serum resistance. The use of hybrid O35E-MC317 uspA2 genes showed that the N-terminal half of the O35E protein contained a 102-amino-acid region that was involved in the expression of serum resistance. In addition, when the uspA2 genes from strains O35E and MC317 were cloned and expressed in Haemophilus influenzae DB117, only the O35E UspA2 protein caused a significant increase in the serum resistance of the H. influenzae recombinant strain. These results prove that the UspA2 protein is directly involved in the expression of serum resistance by certain M. catarrhalis strains.

Identification of a trypanocidal factor againstTrypanosoma equiperdumin normal human serum

Parasitology ◽  
1989 ◽  
Vol 98 (3) ◽  
pp. 401-407 ◽  
Author(s):  
G. Verducci ◽  
S. Perito ◽  
R. Rossi ◽  
E. Mannarino ◽  
F. Bistoni ◽  
...  
Keyword(s):  
Human Serum ◽  
Gel Filtration ◽  
Density Lipoprotein ◽  
Natural Antibodies ◽  
Normal Human Serum ◽  
Mouse Serum ◽  
Trypanocidal Activity ◽  
Normal Human

SUMMARYNormal human serum (HS) contains trypanolytic activity and agglutinins toTrypanosoma equiperdum, while such activities are not found in sera from a range of animals susceptible to infection. HS given toT. equiperdum-infected mice caused a rapid decrease in the number of circulating trypanosomes and protection from lethal infection. Trypanolytic activity of human serum was found to be associated, after DEAE chromatography and Sephadex G-200 gel filtration, with the fraction containing 19S antibodies. Immunofluorescence assays confirmed a binding of human IgM and C1qcomplement component onto the surface ofT. equiperdum. Anti-T. equiperdumactivity of HS was specifically directed toT. equiperdumsurface components and not to some mouse serum components adsorbed on parasites during the growth in the host, because HS adsorbedin vivoin CD-1 mice retained full protective and agglutinating properties. Trypanocidal activity appears in human serum about the 7th month after birth and persists until late in life. On the contrary, human purified high-density lipoprotein had no significantin vitroorin vivotrypanocidal activity. In conclusion, strong natural anti-T. equiperdumactivity in human serum was mainly mediated by natural antibodies of the IgM class. The presence of natural IgM active againstT. equiperdumin HS could represent one of the natural mechanisms of resistance of refractory hosts against trypanosome infections. This phenomenon provides further evidence that host specificity of trypanosomes may be partly conditioned by the presence of natural antibodies.

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