Comparison of anti-pertussis toxin ELISA and agglutination assays to assess immune responses to pertussis.
BACKGROUND
The goal of our study was to compare the following two methods of assessment of pertussis post-vaccination immunity: bacterial agglutination test and pertussis toxin enzyme-linked immunosorbent assay (ELISA).


METHODS
The study was carried out in Perm Region, Russia. We measured pertussis immunity using two serological methods: ELISA of IgG to pertussis toxin (PT) and the agglutination test (AT) among 135 children, in the age range from 2 months to 17 years old. The immunization schedule included four doses of DTwP: at 3, 4.5 and 6 months of age and a booster at 18 months. All participants were divided into six age groups.


RESULTS
The percentage of samples with IgG level less than the detection limit in vaccinated children was 52.2%. The total seropositivity rate (the percent of children with agglutinin titres ≥1:160) in vaccinated children was 47.8%. Only a weak association was observed between agglutinin and anti-PT IgG titres (R = .3). Neither the primary nor the booster vaccination with DTwP influenced the IgG levels in children. Agglutinin titres significantly increased after vaccination and declined 5 years after the booster dose. Significant growth of IgG concentration was observed in 11-year-olds, indicating the presence of B. pertussis circulation in the childhood population.


CONCLUSIONS
Based on the obtained results and the results of other authors, we summarize that anti-PT ELISA should be carefully used to assess the population immunity to pertussis. Currently, there is neither a serological test that accurately determines the protection against pertussis nor a distinctive criterion of protection that can be applied in seroepidemiological studies.
a Perm State National Research University , Perm , Russia.
Pavel
P
Khramtsov
b Institute of Ecology and Genetics of Microorganisms, Ural Branch of the Russian Academy of Sciences , Perm , Russia.
Maria
M
Bochkova
b Institute of Ecology and Genetics of Microorganisms, Ural Branch of the Russian Academy of Sciences , Perm , Russia.
Valeria
V
Timganova
b Institute of Ecology and Genetics of Microorganisms, Ural Branch of the Russian Academy of Sciences , Perm , Russia.
Svetlana
S
Zamorina
b Institute of Ecology and Genetics of Microorganisms, Ural Branch of the Russian Academy of Sciences , Perm , Russia.|c Ural Federal University named after the First President of Russia B.N.Yeltsin , Ekaterinburg , Russia.
Mikhail
M
Rayev
D000293:Adolescent; D000372:Agglutination Tests / Q000379:methods*; D000907:Antibodies, Bacterial / Q000097:blood* / Q000276:immunology; D001886:Bordetella pertussis / Q000276:immunology; D002648:Child; D002675:Child, Preschool; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods*; D006801:Humans; D007074:Immunoglobulin G / Q000097:blood* / Q000276:immunology; D007223:Infant; D057230:Limit of Detection; D037342:Pertussis Toxin / Q000037:antagonists & inhibitors / Q000276:immunology*; D010567:Pertussis Vaccine / Q000276:immunology*; D014917:Whooping Cough / Q000276:immunology / Q000517:prevention & control
D000907:Antibodies, Bacterial; D007074:Immunoglobulin G; D010567:Pertussis Vaccine; D037342:Pertussis Toxin
Agglutination; ELISA; immunity; pertussis; protection