scholarly journals Lysis of measles virus-infected cells by the purified cytolytic alternative complement pathway and antibody.

1979 ◽  
Vol 150 (3) ◽  
pp. 445-454 ◽  
Author(s):  
J G Patrick Sissons ◽  
R D Schreiber ◽  
L H Perrin ◽  
N R Cooper ◽  
H J Müller-Eberhard ◽  
...  
Keyword(s):  
Infected Cell ◽  
Human Serum ◽  
Serum Protein ◽  
Hela Cells ◽  
Measles Virus ◽  
Alternative Pathway ◽  
Complement Pathway ◽  
Virus Infected Cell ◽  
Alternative Complement ◽  
Infected Cells

The dependence of antibody-and-complement-mediated lysis of virus-infected cells on the alternative pathway was examined utilizing the isolated cytolytic alternative pathway--a system consisting of the six purified proteins of the alternative pathway of activation (C3, factors B and D, beta 1H, C3b inactivator and properdin), and the five proteins of the membrane attack pathway (C5--9) of complement. HeLa cells acutely infected with measles virus were lysed by anti-viral IgG and the isolated cytolytic alternative pathway with an efficiency comparable to whole human serum. IgG and its F(ab')2 fragment were equally effective in inducing lysis by the isolated cytolytic alternative pathway, binding of approximately equal to 5 X 10(7) molecules per cell being required for 50% lysis; in contrast, no lysis occurred when equivalen or greater amounts of Fab' were bound to the virus-infected cell. Properdin was required for lysis. No lysis occurred if properdin was deleted from the isolated cytolytic alternative pathway, and lysis was diminished by 80% in properdin-depleted serum. Uptake of [125I]C3b from the isolated alternative pathway onto measles virus-infected cells occurred in the absence of properdin, but was accelerated in the presence of properdin. The 11 proteins of the isolated cytolytic alternative pathway are thus sufficient for lysis of measles virus-infected cells bearing anti-viral IgG or F(ab')2 without any other serum protein.

scholarly journals Cell surface activation of the alternative complement pathway by the fusion protein of measles virus

2004 ◽  
Vol 85 (6) ◽  
pp. 1665-1673 ◽  
Author(s):  
Patricia Devaux ◽  
Dale Christiansen ◽  
Sébastien Plumet ◽  
Denis Gerlier
Keyword(s):  
Cell Surface ◽  
Measles Virus ◽  
Alternative Pathway ◽  
Surface Expression ◽  
Activation Mechanism ◽  
Cell Surface Expression ◽  
Target Cells ◽  
Surface Activation ◽  
Complement Pathway ◽  
Infected Cells

Measles virus (MV)-infected cells are activators of the alternative human complement pathway, resulting in high deposition of C3b on the cell surface. Activation was observed independent of whether CD46 was used as a cellular receptor and did not correlate with CD46 down-regulation. The virus itself was an activator of the alternative pathway and was covered by C3b/C3bi, resulting in some loss in infectivity without loss of virus binding to target cells. The cell surface expression of MV fusion (F), but not haemagglutinin, envelope protein resulted in complement activation of the Factor B-dependent alternative pathway in a dose-dependent manner and F–C3b complexes were formed. The underlying activation mechanism was not related to any decrease in cell surface expression of the complement regulators CD46 and CD55. The C3b/C3bi coating of MV-infected cells and virus should ensure enhanced targeting of MV antigens to the immune system, through binding to complement receptors.

scholarly journals Complement 1 Inhibitor Is a Regulator of the Alternative Complement Pathway

2001 ◽  
Vol 194 (11) ◽  
pp. 1609-1616 ◽  
Author(s):  
Haixiang Jiang ◽  
Eric Wagner ◽  
Huamei Zhang ◽  
Michael M. Frank
Keyword(s):  
Human Serum ◽  
Paroxysmal Nocturnal Hemoglobinuria ◽  
Alternative Pathway ◽  
Alternative Complement Pathway ◽  
Complement Pathway ◽  
Cobra Venom Factor ◽  
Factor B ◽  
Alternative Complement ◽  
Pathway Function ◽  
Cross Competition

We studied complement 1 inhibitor (C1-INH) as an inhibitor of the alternative complement pathway. C1-INH prevented lysis, induced by the alternative complement pathway, of paroxysmal nocturnal hemoglobinuria (PNH) erythrocytes in human serum. It inhibited the binding of both factors B and C3 to PNH and rabbit erythrocytes and blocked the ability of factor B to restore alternative-pathway function in factor B–depleted serum. C1-INH did not bind to factors B or D but did bind to immobilized C3b and cobra venom factor (CVF), a C3b analogue. C1-INH prevented factor B from binding to CVF-coated beads and dissociated bound factor B from such beads. Factor B and C1-INH showed cross competition in binding to CVF-coated beads. Factor D cleaved factor B into Bb and Ba in the presence of C3b. Cleavage was markedly inhibited when C3b was preincubated with C1-INH. C1-INH inhibited the formation of CVFBb and decreased the C3 cleavage. Removal of C1-INH from serum, in the presence of Mg-EGTA with an anti–C1-INH immunoabsorbant, markedly increased alternative-pathway lysis. C1-INH interacts with C3b to inhibit binding of factor B to C3b. At physiologic concentrations, it is a downregulator of the alternative pathway convertase.

scholarly journals Simple Method To Distinguish between Primary and Secondary C3 Deficiencies

2003 ◽  
Vol 10 (2) ◽  
pp. 216-220
Author(s):  
Marlene Pereira de Carvalho Florido ◽  
Patrícia Ferreira de Paula ◽  
Lourdes Isaac
Keyword(s):  
Human Serum ◽  
Complement System ◽  
Factor H ◽  
Normal Human Serum ◽  
Alternative Complement Pathway ◽  
Complement Pathway ◽  
Factor B ◽  
Alternative Complement ◽  
Normal Human ◽  
The Complement System

ABSTRACT Due to the increasing numbers of reported clinical cases of complement deficiency in medical centers, clinicians are now more aware of the role of the complement system in the protection against infections caused by microorganisms. Therefore, clinical laboratories are now prepared to perform a number of diagnostic tests of the complement system other than the standard 50% hemolytic component assay. Deficiencies of alternative complement pathway proteins are related to severe and recurrent infections; and the application of easy, reliable, and low-cost methods for their detection and distinction are always welcome, notably in developing countries. When activation of the alternative complement pathway is evaluated in hemolytic agarose plates, some but not all human sera cross-react to form a late linear lysis. Since the formation of this linear lysis is dependent on C3 and factor B, it is possible to use late linear lysis to routinely screen for the presence of deficiencies of alternative human complement pathway proteins such as factor B. Furthermore, since linear lysis is observed between normal human serum and primary C3-deficient serum but not between normal human serum and secondary C3-deficient serum caused by the lack of factor H or factor I, this assay may also be used to discriminate between primary and secondary C3 deficiencies.

scholarly journals Mechanism of injury of virus-infected cells by antiviral antibody and complement: participation of IgG, F(ab')2, and the alternative complement pathway.

1976 ◽  
Vol 143 (5) ◽  
pp. 1027-1041 ◽  
Author(s):  
L H Perrin ◽  
B S Joseph ◽  
N R Cooper ◽  
M B Oldstone
Keyword(s):  
Measles Virus ◽  
Influenza A ◽  
Igg Antibodies ◽  
Factor B ◽  
Alternative Complement ◽  
Human Sera ◽  
Antiviral Antibody ◽  
Infected Cells ◽  
Virus Influenza

Antibody-mediated C-dependent lysis of cell lines infected with herpes simplex type 1 virus, influenza A degrees virus, measles virus, and mumps virus occurred by the alternative C pathway with the participation of IgG antibodies. Lysis occurred only with immune human sera, Mg++ EGTA immune sera, and immune sera depleted of C4 or treated with Fab anti-C4. Lysis did not occur with nonimmune sera, Mg++ EDTA immune sera, and immune sera heated 50 degrees C for 25 min, depleted of factor B or treated with Fab antifactor B. Lysis was restored to heated and factor B immunodepleted immune sera by addition of factor B, but not by addition of an excess of C2. Further studies showed that lysis of HeLa cells infected with measles virus was induced by both immune IgG and F(ab')2 but not Fab' in the presence of a nonantibody-containing human C source. Lysis of measles virus-infected cells was also indpendent of movement of viral antigens on the surface of the infected cells, as inhibition of viral antigen capping by cytochalasin B or sodium azide was not associated with abrogation of immune lysis.

scholarly journals Activation of the guinea pig alternative complement pathway by mouse IgA immune complexes.

1982 ◽  
Vol 155 (1) ◽  
pp. 231-247 ◽  
Author(s):  
G Pfaffenbach ◽  
M E Lamm ◽  
I Gigli
Keyword(s):  
Guinea Pig ◽  
Immune Complexes ◽  
Alternative Pathway ◽  
Fluid Phase ◽  
Alternative Complement Pathway ◽  
Complement Pathway ◽  
Myeloma Protein ◽  
Pathway Activation ◽  
Alternative Complement ◽  
Iga Immune Complexes

Activation of the complement system by IgA was investigated with immune complexes containing a mouse IgA myeloma protein with specificity for phosphorylcholine linked to bovine serum albumin (PC-BSA). These IgA anti-PC-BSA immune complexes activated the alternative complement pathway in mouse and guinea pig serum, while human complement was not affected. The activation proceeded with consumption of C3 but little or no consumption of C5. C3 did not bind to the IgA immune complexes during complement activation although it did bind covalently to IgG immune complexes. It is suggested that IgA immune complexes do not supply a suitable surface for C3 binding and effective alternative pathway convertase assembly; therefore, cleavage is limited and occurs primarily in the fluid phase. Without C3 binding, C5 cleavage does not occur nor can the alternative pathway activation proceed to the amplification step.

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