scholarly journals Complement Evasion by Borrelia burgdorferi: Serum-Resistant Strains Promote C3b Inactivation

2001 ◽  
Vol 69 (6) ◽  
pp. 3685-3691 ◽  
Author(s):  
Antti Alitalo ◽  
Taru Meri ◽  
Lasse Rämö ◽  
T. Sakari Jokiranta ◽  
Tero Heikkilä ◽  
...  
Keyword(s):  
Borrelia Burgdorferi ◽  
Human Serum ◽  
Radioligand Binding ◽  
Surface Protein ◽  
Sensu Stricto ◽  
Factor H ◽  
Factor I ◽  
Normal Human ◽  
Resistant Strains ◽  
Characteristic Features

ABSTRACT The most characteristic features of the Lyme disease pathogens, theBorrelia burgdorferi sensu lato (s.l.) group, are their ability to invade tissues and to circumvent the immune defenses of the host for extended periods of time, despite elevated levels of borrelia-specific antibodies in serum and other body fluids. Our aim in the present study was to determine whether B. burgdorferi is able to interfere with complement (C) at the level of C3 by accelerating C3b inactivation and thus to inhibit the amplification of the C cascade. Strains belonging to different genospecies (Borrelia garinii, B. burgdorferi sensu stricto, and Borrelia afzelii) were compared for their sensitivities to normal human serum and abilities to promote factor I-mediated C3b degradation. B. burgdorferi sensu stricto and B. afzelii strains were found to be serum resistant. When the spirochetes were incubated with radiolabeled C3b, factor I-mediated degradation of C3b was observed in the presence of C-resistant B. afzelii(n = 3) and B. burgdorferi sensu stricto (n = 1) strains but not in the presence of C-sensitive B. garinii (n = 7) strains or control bacteria (Escherichia coli,Staphylococcus aureus, and Enterococcus faecalis). Immunoblotting and radioligand binding analyses showed that the C-resistant strains had the capacity to acquire the C inhibitors factor H and factor H-like protein 1 (FHL-1) from growth medium and human serum. A novel surface protein with an apparent molecular mass of 35 kDa was found to preferentially bind to the N terminus region of factor H. Thus, the serum-resistant B. burgdorferi s.l. strains can circumvent C attack by binding the C inhibitors factor H and FHL-1 to their surfaces and promoting factor I-mediated C3b degradation.

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 Borrelia burgdorferi Complement Regulator-Acquiring Surface Protein 1 of the Lyme Disease Spirochetes Is Expressed in Humans and Induces Antibody Responses Restricted to Nondenatured Structural Determinants

2006 ◽  
Vol 74 (12) ◽  
pp. 7024-7028 ◽  
Author(s):  
Evelyn Rossmann ◽  
Veronique Kitiratschky ◽  
Heidelore Hofmann ◽  
Peter Kraiczy ◽  
Markus M. Simon ◽  
...  
Keyword(s):  
Lyme Disease ◽  
Borrelia Burgdorferi ◽  
Surface Protein ◽  
Factor H ◽  
Antibody Responses ◽  
Dominant Factor ◽  
Serum Samples ◽  
Structural Determinants ◽  
Pathogen Persistence ◽  
Complement Regulator

ABSTRACT Borrelia burgdorferi complement regulator-acquiring surface protein 1 (CRASP-1), the dominant factor H and FHL-1-binding protein of the Lyme disease spirochete B. burgdorferi, is implicated in pathogen persistence and was recently reported to be nonimmunogenic in humans. Here we show that serum samples from Lyme disease patients contain antibodies with exclusive specificity for nondenatured structural determinants of CRASP-1.

scholarly journals Cleavage of Complement C3b to iC3b on the Surface of Staphylococcus aureus Is Mediated by Serum Complement Factor I

2004 ◽  
Vol 72 (5) ◽  
pp. 2858-2863 ◽  
Author(s):  
K. M. Cunnion ◽  
P. S. Hair ◽  
E. S. Buescher
Keyword(s):  
Staphylococcus Aureus ◽  
Human Serum ◽  
Serum Proteins ◽  
Regulatory Protein ◽  
Factor H ◽  
Complement Factor ◽  
Serum Factor ◽  
Complement Protein ◽  
Factor I ◽  
Serotype 5

ABSTRACT Complement-mediated opsonization of Staphylococcus aureus bearing the dominant capsule serotypes, serotypes 5 and 8, remains incompletely understood. We have previously shown that complement plays a vital role in the efficient phagocytosis of a serotype 5 S. aureus strain and that the opsonic fragments of the central complement protein C3, C3b and iC3b, were present on the bacterial surface after incubation in human serum. In the present studies, C3b and iC3b were found on several serotype 5 and 8 S. aureus strains after incubation in human serum. Using purified classical activation pathway complement proteins and the Western blot assay, we showed that when C3b was generated on the S. aureus surface no iC3b fragments were found, suggesting that other serum proteins may be required for cleaving C3b to iC3b. When C3b-coated S. aureus was incubated with serum factor I, a complement regulatory protein, iC3b was generated. Purified factor H, a serum protein cofactor for factor I, did not enhance factor I-mediated cleavage of C3b. These findings suggest that C3b cleavage to iC3b on S. aureus is mediated by serum factor I and does not require factor H.

scholarly journals Borrelia burgdorferi Escape Mutants That Survive in the Presence of Antiserum to the OspA Vaccine Are Killed When Complement Is Also Present

1998 ◽  
Vol 66 (6) ◽  
pp. 2540-2546 ◽  
Author(s):  
Mónica Solé ◽  
Carlos Bantar ◽  
Karl Indest ◽  
Yan Gu ◽  
Ramesh Ramamoorthy ◽  
...  
Keyword(s):  
Borrelia Burgdorferi ◽  
Protein A ◽  
Surface Protein ◽  
Sensu Stricto ◽  
Antibody Concentration ◽  
Initial Attempt ◽  
Outer Surface Protein A ◽  
Escape Mutants ◽  
Low Passage

ABSTRACT As an initial attempt to investigate the possible role of outer surface protein A (OspA) escape mutants of Borrelia burgdorferi in decreasing the efficacy of the OspA vaccine, mutants of the HB19 strain of B. burgdorferi sensu stricto were selected in vitro from an uncloned, low-passage-number isolate. The antiserum used for selection was obtained from rhesus monkeys that had been given a vaccine of the same formulation and dose, and by the same route of administration, as that given to humans in several trials. All of the mutants selected in liquid medium and subsequently cloned twice in solid medium expressed a single abundant protein of 28 to 34 kDa instead of both OspA and OspB. Depending on the mutant, this protein reacted strongly, weakly, or not detectably with the anti-OspA antibody used for selection. Analysis of the ospAB locus of each of four representatives from these three groups of mutants by PCR with oligonucleotide primers that hybridize to flanking regions of theospAB operon, and of the corresponding phenotype with monoclonal antibodies that bind to the amino or carboxyl terminus of the OspA or OspB polypeptide, indicated that in all cases a deletion within the operon had occurred. Spirochetes from the four mutant strains chosen for further analysis could be killed in antibody-dependent, complement-mediated killing assays with the selecting anti-OspA antibody, despite their resistance to killing with this antibody in the absence of complement. Complement-mediated killing occurred at an antibody concentration higher than that required to kill wild-type spirochetes. If anti-OspA antibody acts only within the tick, where complement is probably ineffective due to tick-derived decomplementing factors, then OspA escape mutants, if infectious, could seriously diminish the efficacy of OspA vaccines. On the other hand, if the killing of B. burgdorferi with anti-OspA antibody also takes place within the human host, then our results indicate that chimeric/deletion escape mutants will be killed as well.

scholarly journals Clumping Factor A Interaction with Complement Factor I Increases C3b Cleavage on the Bacterial Surface of Staphylococcus aureus and Decreases Complement-Mediated Phagocytosis

2010 ◽  
Vol 78 (4) ◽  
pp. 1717-1727 ◽  
Author(s):  
Pamela S. Hair ◽  
Charlene G. Echague ◽  
Amber M. Sholl ◽  
Justin A. Watkins ◽  
Joan A. Geoghegan ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Surface Protein ◽  
Factor H ◽  
Complement Factor ◽  
Wild Type ◽  
Bacterial Surface ◽  
Complement Control Protein ◽  
Factor I ◽  
Protein Factor ◽  
Fibrinogen Binding

ABSTRACT The human complement system is important in the immunological control of Staphylococcus aureus infection. We showed previously that S. aureus surface protein clumping factor A (ClfA), when expressed in recombinant form, bound complement control protein factor I and increased factor I cleavage of C3b to iC3b. In the present study, we show that, compared to the results for the wild type, when isogenic ClfA-deficient S. aureus mutants were incubated in serum, they bound less factor I, generated less iC3b on the bacterial surface, and bound fewer C3 fragments. It has been shown previously that two amino acids in ClfA (P336 and Y338) are essential for fibrinogen binding. However, S. aureus expressing ClfA(P336A Y338S) was less virulent than ClfA-deficient strains in animal models. This suggested that ClfA contributed to S. aureus virulence by a mechanism different than fibrinogen binding. In the present study, we showed that S. aureus expressing ClfA(P336A Y338S) was more susceptible to complement-mediated phagocytosis than a ClfA-null mutant or the wild type. Unlike ClfA, ClfA(P336A Y338S) did not enhance factor I cleavage of C3b to iC3b and inhibited the cofactor function of factor H. Fibrinogen enhanced factor I binding to ClfA and the S. aureus surface. Twenty clinical S. aureus strains all expressed ClfA and bound factor I. High levels of factor I binding by clinical strains correlated with poor phagocytosis. In summary, our results suggest that the interaction of ClfA with factor I contributes to S. aureus virulence by a complement-mediated mechanism.

scholarly journals THE PROPERDIN SYSTEM AND IMMUNITY

1956 ◽  
Vol 103 (5) ◽  
pp. 553-575 ◽  
Author(s):  
Alastair C. Wardlaw ◽  
Louis Pillemer
Keyword(s):  
Human Serum ◽  
Bactericidal Activity ◽  
Quantitative Relationship ◽  
Normal Human Serum ◽  
Natural Resistance ◽  
Bactericidal Action ◽  
Individual Strain ◽  
Normal Human ◽  
Resistant Strains ◽  
The Individual

Methods for the preparation and standardization of reagents suitable for studies on the bactericidal action of the properdin system are described. The preparation and properties of serum free of properdin (RPb) are presented in detail because of the necessity for a suitable RPb in these studies. The properdin system is responsible for the bactericidal action of normal human serum against a variety of microorganisms. The present work shows that the removal of properdin from serum also removes bactericidal activity. Addition of properdin to properdin-deficient serum restores bactericidal activity. A quantitative relationship exists between the final properdin concentration and bactericidal activity against sensitive organisms. The possibilities of a bactericidal assay for properdin are discussed. It is demonstrated that, in addition to properdin, the four components of complement (present in RPb) are necessary for the destruction of properdinsensitive bacteria. If any component is missing, bactericidal activity is lost; when the component is replaced, bactericidal activity is restored. Magnesium is also necessary for the bactericidal activity of the properdin system. Maximal bactericidal activity is obtained with magnesium concentrations similar to that of normal human serum (10–3 to 10–4 M). The bactericidal activity of the properdin system occurs only at temperatures above 15°. Resistant strains have been encountered in species of bacteria sensitive to the properdin system. Resistance or sensitivity is a characteristic of the individual strain and not of the species. The widespread occurrence of the properdin system in normal mammalian serum and the variety of bacteria destroyed by it suggest that the properdin system is a factor in natural resistance.

scholarly journals Contribution of the Infection-Associated Complement Regulator-Acquiring Surface Protein 4 (ErpC) to Complement Resistance ofBorrelia burgdorferi

2012 ◽  
Vol 2012 ◽  
pp. 1-12 ◽  
Author(s):  
Claudia Hammerschmidt ◽  
Teresia Hallström ◽  
Christine Skerka ◽  
Reinhard Wallich ◽  
Brian Stevenson ◽  
...  
Keyword(s):  
Human Serum ◽  
Magnetic Beads ◽  
Surface Protein ◽  
Factor H ◽  
Surface Proteins ◽  
Complement Components ◽  
Complement Resistance ◽  
Complement Regulators ◽  
Complement Regulator ◽  
The Impact

Borrelia burgdorferievades complement-mediated killing by interacting with complement regulators through distinct complement regulator-acquiring surface proteins (CRASPs). Here, we extend our analyses to the contribution of CRASP-4 in mediating complement resistance ofB. burgdorferiand its interaction with human complement regulators. CRASP-4 (also known as ErpC) was immobilized onto magnetic beads and used to capture proteins from human serum. Following Western blotting, factor H (CFH), CFH-related protein 1 (CFHR1), CFHR2, and CFHR5 were identified as ligands of CRASP-4. To analyze the impact of native CRASP-4 on mediating survival of serum-sensitive cells in human serum, aB. gariniistrain was generated that ectopically expresses CRASP-4. CRASP-4-producing bacteria bound CFHR1, CFHR2, and CFHR5 but not CFH. In addition, transformed spirochetes deposited significant amounts of lethal complement components on their surface and were susceptible to human serum, thus indicating that CRASP-4 plays a subordinate role in complement resistance ofB. burgdorferi.

scholarly journals Borrelia burgdorferi Regulates Expression of Complement Regulator-Acquiring Surface Protein 1 during the Mammal-Tick Infection Cycle

2005 ◽  
Vol 73 (11) ◽  
pp. 7398-7405 ◽  
Author(s):  
Kate von Lackum ◽  
Jennifer C. Miller ◽  
Tomasz Bykowski ◽  
Sean P. Riley ◽  
Michael E. Woodman ◽  
...  
Keyword(s):  
Borrelia Burgdorferi ◽  
Immune Evasion ◽  
Expression Patterns ◽  
Surface Protein ◽  
Factor H ◽  
Complement Factor ◽  
Human Pathogens ◽  
Infection Cycle ◽  
Tick Infection ◽  
Complement Regulator

ABSTRACT During the natural mammal-tick infection cycle, the Lyme disease spirochete Borrelia burgdorferi comes into contact with components of the alternative complement pathway. B. burgdorferi, like many other human pathogens, has evolved the immune evasion strategy of binding two host-derived fluid-phase regulators of complement, factor H and factor H-like protein 1 (FHL-1). The borrelial complement regulator-acquiring surface protein 1 (CRASP-1) is a surface-exposed lipoprotein that binds both factor H and FHL-1. Analysis of CRASP-1 expression during the mammal-tick infectious cycle indicated that B. burgdorferi expresses this protein during mammalian infection, supporting the hypothesized role for CRASP-1 in immune evasion. However, CRASP-1 synthesis was repressed in bacteria during colonization of vector ticks. Analysis of cultured bacteria indicated that CRASP-1 is differentially expressed in response to changes in pH. Comparisons of CRASP-1 expression patterns with those of other infection-associated B. burgdorferi proteins, including the OspC, OspA, and Erp proteins, indicated that each protein is regulated through a unique mechanism.

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