scholarly journals Simultaneous Determination of Antibodies to Pertussis Toxin and Adenylate Cyclase Toxin Improves Serological Diagnosis of Pertussis

Diagnostics ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 180
Author(s):  
Aapo Knuutila ◽  
Alex-Mikael Barkoff ◽  
Jussi Mertsola ◽  
Radim Osicka ◽  
Peter Sebo ◽  
...  
Keyword(s):  
Adenylate Cyclase ◽  
Pertussis Toxin ◽  
Serological Diagnosis ◽  
Promising Candidate ◽  
Flow Test ◽  
Before And After ◽  
Adenylate Cyclase Toxin ◽  
Lateral Flow Test ◽  
Acellular Vaccines

Serological diagnosis of pertussis is mainly based on anti-pertussis toxin (PT) IgG antibodies. Since PT is included in all acellular vaccines (ACV), serological assays do not differentiate antibodies induced by ACVs and infection. Adenylate cyclase toxin (ACT) is not included in the ACVs, which makes it a promising candidate for pertussis serology with the specific aim of separating infection- and ACV-induced antibodies. A multiplex lateral flow test with PT and ACT antigens was developed to measure serum antibodies from pertussis-seropositive patients (n = 46), healthy controls (n = 102), and subjects who received a booster dose of ACV containing PT, filamentous hemagglutinin, and pertactin (n = 67) with paired sera collected before and one month after the vaccination. If the diagnosis was solely based on anti-PT antibodies, 98.5–44.8% specificity (before and after vaccination, respectively) and 78.2% sensitivity were achieved, whereas if ACT was used in combination with PT, the sensitivity of the assay increased to 91.3% without compromising specificity. No increase in the level of anti-ACT antibodies was found after vaccination. This exploratory study indicates that the use of ACT for serology would be beneficial in combination with a lower quantitative cutoff for anti-PT antibodies, and particularly in children and adolescents who frequently receive booster vaccinations.

scholarly journals Pertussis Toxin and Adenylate Cyclase Toxin Provide a One-Two Punch for Establishment of Bordetella pertussis Infection of the Respiratory Tract

2005 ◽  
Vol 73 (5) ◽  
pp. 2698-2703 ◽  
Author(s):  
Nicholas H. Carbonetti ◽  
Galina V. Artamonova ◽  
Charlotte Andreasen ◽  
Nicholas Bushar
Keyword(s):  
Adenylate Cyclase ◽  
Respiratory Tract ◽  
Pertussis Toxin ◽  
Bordetella Pertussis ◽  
Type Strain ◽  
Wild Type Strain ◽  
Infection Model ◽  
Wild Type ◽  
Adenylate Cyclase Toxin ◽  
Tract Infections

ABSTRACT Previously we found that pertussis toxin (PT), an exotoxin virulence factor produced by Bordetella pertussis, plays an important early role in colonization of the respiratory tract by this pathogen, using a mouse intranasal infection model. In this study, we examined the early role played by another exotoxin produced by this pathogen, adenylate cyclase toxin (ACT). By comparing a wild-type strain to a mutant strain (ΔCYA) with an in-frame deletion of the cyaA gene encoding ACT, we found that the lack of ACT confers a significant peak (day 7) colonization defect (1 to 2 log10). In mixed-infection experiments, the ΔCYA strain was significantly outcompeted by the wild-type strain, and intranasal administration of purified ACT did not increase colonization by ΔCYA. These data suggest that ACT benefits the bacterial cells that produce it and, unlike PT, does not act as a soluble factor benefiting the entire infecting bacterial population. Comparison of lower respiratory tract infections over the first 4 days after inoculation revealed that the colonization defect of the PT deletion strain was apparent earlier than that of ΔCYA, suggesting that PT plays an earlier role than ACT in the establishment of B. pertussis infection. Examination of cells in the bronchoalveolar lavage fluid of infected mice revealed that, unlike PT, ACT does not appear to inhibit neutrophil influx to the respiratory tract early after infection but may combat neutrophil activity once influx has occurred.

scholarly journals Bordetella pertussis Virulence Factors Affect Phagocytosis by Human Neutrophils

2000 ◽  
Vol 68 (3) ◽  
pp. 1735-1739 ◽  
Author(s):  
Christine L. Weingart ◽  
Alison A. Weiss
Keyword(s):  
Adenylate Cyclase ◽  
Virulence Factors ◽  
Pertussis Toxin ◽  
Bordetella Pertussis ◽  
Type Strain ◽  
Wild Type Strain ◽  
Human Neutrophils ◽  
Wild Type ◽  
Dermonecrotic Toxin ◽  
Adenylate Cyclase Toxin

ABSTRACT The interaction between human neutrophils and wild-typeBordetella pertussis or mutants expressing altered lipopolysaccharide or lacking virulence factors—pertussis toxin, adenylate cyclase toxin, dermonecrotic toxin, filamentous hemagglutinin (FHA), pertactin, or BrkA—was examined. In the absence of antibodies, the wild-type strain and the mutants, with the exception of mutants lacking FHA, attached efficiently to neutrophils. The addition of opsonizing antibodies caused a significant reduction (approximately 50%) in attachment of the wild-type strain and most of the mutants expressing FHA, suggesting that bacterium-mediated attachment is more efficient than Fc-mediated attachment. Phagocytosis was also examined. In the absence of antibodies, about 12% of the wild-type bacteria were phagocytosed. Opsonization caused a statistically significant reduction in phagocytosis (to 3%), possibly a consequence of reduced attachment. Phagocytosis of most of the mutants was similar to that of the wild type, with the exception of the mutants lacking adenylate cyclase toxin. About 70% of the adenylate cyclase toxin mutants were phagocytosed, but only in the presence of opsonizing antibody, suggesting that Fc receptor-mediated signaling may be needed for phagocytosis. These studies indicate that FHA mediates attachment ofB. pertussis to neutrophils, but adenylate cyclase toxin blocks phagocytosis.

scholarly journals Methods for Determination of the Presence of Allergens in Foods

2014 ◽  
Vol 10 (3-4) ◽  
Author(s):  
Željka Marjanović-Balaban ◽  
Radoslav Grujić ◽  
Biljana Pećanac ◽  
Dijana Jelić
Keyword(s):  
Analytical Techniques ◽  
Enzyme Linked Immunosorbent Assay ◽  
World Population ◽  
Chain Reaction ◽  
Advantages And Disadvantages ◽  
Flow Test ◽  
The World ◽  
Polymerase Chain ◽  
Lateral Flow Test

Recent studies indicate that 2-4% of the world population is sensitive to the presence of allergens in foods. It is estimated that there are 5-8% allergic children in Europe.This paper presents an overview of the analytical methods which are used in risk analysis and for making decisions in the management of foods that cause allergies in humans.Depending on the purpose of analysis, a variety of analytical techniques can be used: Enzyme-linked immunosorbent assay (ELISA) is recommended for quantitative determination of the composition of ingredients and final products, Lateral flow test (LFD) can be used during routine control of the efficiency of purification and determination of the composition of final products, PCR (polymerase chain reaction)-ELISA and real-time PCR are used to confirm the ELISA results for samples with a low content of allergens or where it is not possible to apply other tests. Mass spectroscopy (MS) can be used as a method for confirming the results of the routine tests and in detecting of small amounts of the allergens. This paper gives an overview of these techniques by listing the advantages and disadvantages of routine food analysis.

Validation of a Rapid Lateral Flow Test for the Simultaneous Determination of β-Lactam Drugs and Flunixin in Raw Milk

2012 ◽  
Vol 75 (7) ◽  
pp. 1270-1277 ◽  
Author(s):  
DAVID DOUGLAS ◽  
KATIE BANASZEWSKI ◽  
RIMA JUSKELIS ◽  
FADWA AL-TAHER ◽  
YANG CHEN ◽  
...  
Keyword(s):  
Simultaneous Determination ◽  
Limit Of Detection ◽  
Agricultural Practices ◽  
Raw Milk ◽  
Lateral Flow ◽  
Penicillin G ◽  
Screening Programs ◽  
Flow Test ◽  
Lateral Flow Test

β-Lactam antibiotics are the most commonly used drugs on dairy farms. β-Lactam residues in milk are kept out of the human milk supply with good agricultural practices and mandatory truck screening performed by the dairy industry under Appendix N of the Pasteurized Milk Ordinance. Flunixin, a nonsteroidal and anti-inflammatory drug, appears in dairy cattle tissue residues with a frequency similar to the occurrence of penicillin G. This creates concern that flunixin residues could be in milk and would go undetected under current milk screening programs. A single test that combines mandatory β-lactam screening with voluntary flunixin screening is an economical approach for monitoring and controlling for potential flunixin or 5-hydroxyflunixin, the primary flunixin metabolite marker in milk. The objective of this study was to validate a β-lactam and flunixin rapid lateral flow test (LFT) and compare the results obtained with a liquid chromatography-triple quadrupole tandem mass spectrometry (LC-MS/MS) method for the simultaneous determination of flunixin and 5-hydroxyflunixin in raw milk with a limit of detection of <1 ppb, equivalent to 1 ng/ml. Using the LFT, three combined manufactured lots of test strips detected penicillin G at 2.0 ppb, ampicillin at 6.8 ppb, amoxicillin at 5.9 ppb, cephapirin at 13.4 ppb, ceftiofur (total metabolites) at 63 ppb, and 5-hydroxyflunixin at 1.9 ppb at least 90% of the time with 95% confidence. The LFT also detected incurred flunixin milk samples that were analyzed with the LC-MS/MS and diluted to tolerance in raw milk. The detection levels for the LFT are lower than the U.S. safe levels or tolerances and qualify the test to be used in compliance with U.S. milk screening programs.

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