Resolution and analysis of ‘native’ and ‘activated’ properdin

Farries, Timothy C.; Finch, J.T.; Lachmann, P. J.; Harrison, Richard A.

doi:10.1042/bj2430507

Cited by 58 publications

(83 citation statements)

References 34 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Other studies have shown a similar effect of higher-order properdin polymers on alternative pathway activity in vitro (39). Encouraged by these findings, we investigated the use of recombinant P n as a bactericidal agent under in vitro and in vivo conditions.…”

Section: Discussionmentioning

confidence: 60%

Low-dose recombinant properdin provides substantial protection againstStreptococcus pneumoniaeandNeisseria meningitidisinfection

Ali

Hayat

Saeed

et al. 2014

Proc. Natl. Acad. Sci. U.S.A.

View full text Add to dashboard Cite

Modern medicine has established three central antimicrobial therapeutic concepts: vaccination, antibiotics, and, recently, the use of active immunotherapy to enhance the immune response toward specific pathogens. The efficacy of vaccination and antibiotics is limited by the emergence of new pathogen strains and the increased incidence of antibiotic resistance. To date, immunotherapy development has focused mainly on cytokines. Here we report the successful therapeutic application of a complement component, a recombinant form of properdin (P n ), with significantly higher activity than native properdin, which promotes complement activation via the alternative pathway, affording protection against N. menigitidis and S. pneumoniae. In a mouse model of infection, we challenged C57BL/6 WT mice with N. menigitidis B-MC58 6 h after i.p. administration of P n (100 μg/mouse) or buffer alone. Twelve hours later, all control mice showed clear symptoms of infectious disease while the P n treated group looked healthy. After 16 hours, all control mice developed sepsis and had to be culled, while only 10% of P n treated mice presented with sepsis and recoverable levels of live Meningococci. In a parallel experiment, mice were challenged intranasally with a lethal dose of S. pneumoniae D39. Mice that received a single i.p. dose of P n at the time of infection showed no signs of bacteremia at 12 h postinfection and had prolonged survival times compared with the salinetreated control group (P < 0.0001). Our findings show a significant therapeutic benefit of P n administration and suggest that its antimicrobial activity could open new avenues for fighting infections caused by multidrug-resistant neisserial or streptococcal strains.

show abstract

Section: Discussionmentioning

confidence: 60%

Low-dose recombinant properdin provides substantial protection againstStreptococcus pneumoniaeandNeisseria meningitidisinfection

Ali

Hayat

Saeed

et al. 2014

Proc. Natl. Acad. Sci. U.S.A.

View full text Add to dashboard Cite

show abstract

“…None of the tested strains bound native properdin, but binding did occur with purified preparations of properdin containing high-order oligomers of aggregated properdin, a phenomenon later demonstrated on zymosan and Streptococcus pneumonia as well (46,47). Aggregates of properdin were shown to appear spontaneously in certain purified preparations on preparation or during long-term storage or freezing and thawing (30,31). These aggregates are artifacts with different properties than serum properdin; for example, they promote fluid-phase complement activation and C3 depletion, as illustrated by the old term "activated properdin" (30,31).…”

Section: Discussionmentioning

confidence: 98%

“…Aggregates of properdin were shown to appear spontaneously in certain purified preparations on preparation or during long-term storage or freezing and thawing (30,31). These aggregates are artifacts with different properties than serum properdin; for example, they promote fluid-phase complement activation and C3 depletion, as illustrated by the old term "activated properdin" (30,31). Ali et al (47) recently showed that recombinant highly polymerized properdin can be a powerful agent to therapeutically combat infections by N. meningitidis and S. pneumonia.…”

Section: Discussionmentioning

confidence: 99%

“…On the other hand, purified properdin is sensitive to aggregation into sticky multimers, and these aggregates, referred to as activated properdin, do not behave as the native form; thus, results with purified properdin must be judged with care (30,31), especially in unfractionated preparations (32). Early preparations of properdin, such as those used in the initial studies by Pillemer et al (1), were later shown to contain impurities and high molecular aggregates of properdin, which were lost when adsorption to zymosan was omitted from the purification protocols (30,33,34). Furthermore, it is crucially important to distinguish between passive binding of properdin to a surface and subsequent activation of AP as a result of this binding.…”

Section: Significancementioning

confidence: 99%

See 1 more Smart Citation

Properdin binding to complement activating surfaces depends on initial C3b deposition

Harboe

Johnson

Nymo

et al. 2017

Proc. Natl. Acad. Sci. U.S.A.

View full text Add to dashboard Cite

Two functions have been assigned to properdin; stabilization of the alternative convertase, C3bBb, is well accepted, whereas the role of properdin as pattern recognition molecule is controversial. The presence of nonphysiological aggregates in purified properdin preparations and experimental models that do not allow discrimination between the initial binding of properdin and binding secondary to C3b deposition is a critical factor contributing to this controversy. In previous work, by inhibiting C3, we showed that properdin binding to zymosan and Escherichia coli is not a primary event, but rather is solely dependent on initial C3 deposition. In the present study, we found that properdin in human serum bound dose-dependently to solid-phase myeloperoxidase. This binding was dependent on C3 activation, as demonstrated by the lack of binding in human serum with the C3-inhibitor compstatin Cp40, in C3-depleted human serum, or when purified properdin is applied in buffer. Similarly, binding of properdin to the surface of human umbilical vein endothelial cells or Neisseria meningitidis after incubation with human serum was completely C3-dependent, as detected by flow cytometry. Properdin, which lacks the structural homology shared by other complement pattern recognition molecules and has its major function in stabilizing the C3bBb convertase, was found to bind both exogenous and endogenous molecular patterns in a completely C3-dependent manner. We therefore challenge the view of properdin as a pattern recognition molecule, and argue that the experimental conditions used to test this hypothesis should be carefully considered, with emphasis on controlling initial C3 activation under physiological conditions.

show abstract

“…Goat anti-human factor H was purchased (Calbiochem-Behring Corp., La Jolla, CA). '25I-factor H was a generous gift of Timothy C. Farries (26).…”

Section: Introductionmentioning

confidence: 99%

Membrane cofactor protein of complement is present on human fibroblast, epithelial, and endothelial cells.

McNearney

Ballard²,

Seya³

et al. 1989

J. Clin. Invest.

108

View full text Add to dashboard Cite

Membrane cofactor protein (MCP) of the complement system is a iC3/C3b binding molecule with cofactor activity that has been identified on all human peripheral blood cells except erythrocytes. Human mononuclear and platelet MCP is dimeric with molecular weights of 68,000 and 63,000 and is expressed in three phenotypic patterns. To further determine its tissue distribution, surface-labeled human fibroblast, epithelial, and endothelial cells and cell lines were assessed for the presence of MCP by iC3 affinity chromatography and by immunoprecipitation with a monospecific anti-MCP rabbit polyclonal antibody. All sources of adult and fetal fibroblast and epithelial cells and cell lines examined and umbilical vein endothelial cells expressed MCP. The molecular weight and phenotypic patterns of MCP were similar to those of peripheral blood cells. MCP was synthesized by fibroblast and epithelial cell lines. Solubilized extracts of these cell lines expressed factor I-dependent cofactor activity for the first cleavage of iC3/C3b which was abrogated by removal of MCP. Expression of MCP was modulated by SV40 transformation of two fetal fibroblast lines. There was a 5-to 10-fold increase in expression of MCP and a preferential expression of the lower species such that the phenotypic desigation was changed. The wide tissue distribution and activity profile of MCP suggest that it is likely to play an important role in the regulation of the complement cascade. IntroductionMembrane cofactor protein (MCP'; formerly named gp45-70) ofcomplement binds iC3/C3b and, less avidly, iC4/C4b (1, 2).

show abstract

Resolution and analysis of ‘native’ and ‘activated’ properdin

Cited by 58 publications

References 34 publications

Low-dose recombinant properdin provides substantial protection againstStreptococcus pneumoniaeandNeisseria meningitidisinfection

Low-dose recombinant properdin provides substantial protection againstStreptococcus pneumoniaeandNeisseria meningitidisinfection

Properdin binding to complement activating surfaces depends on initial C3b deposition

Membrane cofactor protein of complement is present on human fibroblast, epithelial, and endothelial cells.

Contact Info

Product

Resources

About