[Characteristics of Bordetelia pertussis strains isolated from pertussis patients in Moscow by using multilocus sequencing].

AIM: Genotyping of B. pertussis strains isolated from pertussis patients in Moscow. MATERIALS AND METHODS: 53 strains of B. pertussis isolated from pertussis patients in Moscow in 2007 - 2010 as well as 3 vaccine strains currently used in Russia for the production of DTP vaccine were studied by multilocus sequencing (MLST) based on allele combinations of ptxA, ptxC and tcfA genes. RESULTS: A genetic characteristic of B. pertussis strains isolated from pertussis patients in Moscow by using MLST is presented. Allele profile analysis of the studied B. pertussis strains was performed, 4 sequence types (ST) were identified--ST1, ST2, ST3 and ST5, most of the circulating strains (86.7%) were shown to belong to ST5, equal percentage of cases (5.7%)--to ST2 and ST3, and 1.9%--to ST1, while 2 vaccine production strains belong to ST2 and 1 - to ST1. CONCLUSION: Clonal structure of contemporary Moscow strains was shown to be different from strain structure used for the production of DTP vaccine.

Immunogenicity of two diphtheria-tetanus-whole cell pertussis-hepatitis B vaccines in infants: a comparative trial.

AIM: Because of the high mother-to-infant transmissibility of hepatitis B (HB) infection, neonatal vaccination is necessary, but the further doses of HB vaccines can be combined with conventional diphtheria-tetanus-whole cell pertussis (DTPw) vaccines. We compared immunogenicity and reactogenicity of two tetravalent vaccines in Indian children, who after neonatal HB immunization, were vaccinated thrice with one of these vaccines. METHODS: In this open-label randomized study, 287 infants received a dose of an Indian- (Q-Vac (TM )) or European-made (Tritanrix-HB (TM )) tetravalent vaccine at age 6, 10, and 14 weeks. The ELISA antibodies were measured prior to the first and one month after the third dose. Immunogenicity was determined by measuring the seroprotection/seropositivity rates and geometric mean titres (GMT), whereas vaccine reactogenicity was elucidated with diary cards for 7 days following each dose. The potential unsolicited events were queried throughout the whole 3-month study period. RESULTS: Out of the 250 subjects who completed the study, 123 received the Indian and 127 the European vaccine. After 3 doses, the seroprotection/seropositivity rates were 99 % and 100% for diphtheria, 98% and 95% for tetanus, 89% and 94% for pertussis, and 100% and 100% for hepatitis B, respectively. GMT of tetanus antibodies was significantly higher with the Indian vaccine. Low-grade reactogenicity was rather similar in the two vaccine groups, the most common events being local pain, redness, swelling, fever, irritability, unusual crying, drowsiness, and non-specific gastrointestinal symptoms. CONCLUSIONS: Since both immunogenicity and reactogenicity of the two vaccines were almost identical, the Indian vaccine poses a good alternative to the costlier competitor vaccines.

Acellular and "low" pertussis vaccines: adverse events and the role of mutations.

OBJECTIVE: to discuss the current PAHO recommendation that does not support the substitution of traditional cellular DTP vaccine by acellular DTP, and the role of mutations, in humans, as the main cause of rare adverse events, such as epileptic-like convulsions, triggered by pertussis vaccine. DATA REVIEW: the main components related to toxic effects of cellular pertussis vaccines are the lipopolysaccharide of bacterial cell wall and pertussis toxin. The removal of part of lipopolysaccharide layer has allowed the creation of a safer cellular pertussis vaccine, with costs comparable to the traditional cellular vaccine, and which may be a substitute for the acellular vaccine. CONCLUSION: The new methodology introduced by Instituto Butantan allows for the development of a new safer pertussis vaccine with low LPS content (Plow), and the use of the lipopolysaccharide obtained in the process in the production of monophosphoryl lipid A. This component has shown potent adjuvant effect when administered together with influenza inactivated vaccine, making possible to reduce the antigen dose, enhancing the production capacity and lowering costs.

Acellular and "low" pertussis vaccines: adverse events and the role of mutations / Vacinas pertussis acelular e pertussis "low": eventos adversos e o papel das mutações

Objective: to discuss the current PAHO recommendation that does not support the substitution of traditional cellular DTP vaccine by acellular DTP, and the role of mutations, in humans, as the main cause of rare adverse events, such as epileptic-like convulsions, triggered by pertussis vaccine. Data review: the main components related to toxic effects of cellular pertussis vaccines are the lipopolysaccharide of bacterial cell wall and pertussis toxin. The removal of part of lipopolysaccharide layer has allowed the creation of a safer cellular pertussis vaccine, with costs comparable to the traditional cellular vaccine, and which may be a substitute for the acellular vaccine. Conclusion: The new methodology introduced by Instituto Butantan allows for the development of a new safer pertussis vaccine with low LPS content (Plow), and the use of the lipopolysaccharide obtained in the process in the production of monophosphoryl lipid A. This component has shown potent adjuvant effect when administered together with influenza inactivated vaccine, making possible to reduce the antigen dose, enhancing the production capacity and lowering costs.

Objetivo: Discutir as recomendações da WHO-OPAS que não consideram indicada a substituição da vacina DTP celular clássica pela DTP acelular e o papel de mutações, em humanos, como principal causa dos raros eventos de convulsões epileptiformes desencadeadas pela vacina pertussis. Revisão dos dados: Os principais componentes relacionados aos efeitos tóxicos da vacina pertussis celular são o lipopolissacarídio da parede celular da bactéria e a toxina pertussis. A remoção de parte da camada lipopolissacarídica permitiu a criação de uma vacina pertussis celular, mais segura e de custo comparável ao da vacina celular tradicional, podendo substituir a vacina pertussis acelular. Conclusão: A nova vacina pertussis, com baixo teor de LPS (Plow) desenvolvida pelo Instituto Butantan, além de oferecer uma vacina mais segura, permite o aproveitamento do lipopolissacarídeo para a produção de monofosforil lipídeo A. Esse componente mostrou-se potente como adjuvante e altamente eficiente quando administrado com a vacina de influenza, levando à possibilidade de se reduzir a dose de antígeno, aumentando a capacidade de produção e redução dos custos.

Generation of plant-derived recombinant DTP subunit vaccine.

The current diphtheria-tetanus-pertussis (DTP) pediatric vaccine is produced from the corresponding pathogenic bacteria Corynebacterium diphtheriae, Clostridium tetani and Bordetella pertussis; five injected doses of DTaP (acellular) vaccine are required for every child in the standard US vaccination schedule. Because the vaccine is derived from native live sources, adverse effects are possible and production is complex and costly. To address issues of safety, ease of renewability and expense, we used recombinant technology in an effort to develop a subunit DPT vaccine derived in non-pathogenic plant expression systems. Expression of diphtheria toxin (DT), tetanus fragment-C (TetC) and the non-toxic S1 subunit of pertussis toxin (PTX S1) antigenic proteins in soluble form in low-alkaloid tobacco plants and carrot cell cultures allowed efficient downstream purification to levels suitable for intramuscular injection in BALB/c mice. At working concentrations of 5mug per dose, these preparations induced high levels of antigen-specific IgGs in mouse sera. Our results clearly support the feasibility of producing recombinant pediatric vaccine components in plants.

[Evaluation of whole-cell and acellular pertussis vaccines effectiveness in clearance of experimental B. pertussis infection in mice]. / Ocena efektywnosci pelnokomórkowych i bezkomórkowych szczepionek przeciw krztuscowi w eliminacji eksperymentalnego zakazenia myszy Bordetella pertussis.

The study is based on assumption that B. pertussis strains harbouring different allele variants of genes encoding subunit S1 of pertussis toxin and pertactin might be eliminated with different efficiency from lung tissue of mice which were immunized with whole-cell and acellular pertussis vaccines. It has been assumed that strains containing combinations of genes alleles which were not prevalent since 1990-ties are consisting of mutated strains in respect to pertussis toxin subunit S1 and pertactin, and are capable to decrease efficiency of pertussis vaccines. Experiments performed in vivo dealt with activity of tested vaccines against B. pertussis strains of different combinations of ptxS1/prn. The study indicated for lowered efficiency of whole-cell and acellular pertussis vaccines in elimination of mutated strains of B. pertussis from animal lung tissue in comparison with strains currently used for vaccine production.

The rise in pertussis cases urges replacement of chemically-inactivated with genetically-inactivated toxoid for DTP.

The number of pertussis cases reported to the CDC increased from 5158 in 1995 to 21,503 in 2005. Most of the increase was in individuals greater than 10 years of age. This increase occurred also in other developed nations despite high coverage of infants and young children with the acellular pertussis vaccine. In Goteborg Sweden, virtual elimination of pertussis occurred following immunization of 70% of the children less than 10 years old with monocomponent pertussis toxoid (PTx). Immunity following disease or vaccination with either the cellular or acellular pertussis vaccine wanes gradually so that older children and adults may again become susceptible. Currently, PTx is made from chemically-inactivated pertussis toxin (PT). The most immunogenic PTx is made from genetically-inactivated mutant PT that induces higher levels of IgG anti-PT at all ages. Because of its greater immunogenicity, the genetically-inactivated PTx can be expected to be more protective on an individual and on a community basis for a longer duration than the current product. Manufacturers have declined to produce the genetically-inactivated PTx because of the expense required to change to the improved vaccine and not because of scientific issues.

Sequence variation in pertussis S1 subunit toxin and pertussis genes in Bordetella pertussis strains used for the whole-cell pertussis vaccine produced in Poland since 1960: efficiency of the DTwP vaccine-induced immunity against currently circulating B. pertussis isolates.

The present study indicates that the appearance of the B. pertussis harbouring prn2 gene allele variant (not found among clinical isolates before 1990s) may have been induced by long-term vaccination in Poland with DTP-composed vaccine strains presenting exclusively prn1. However, ptxS1A allele of pertussis toxin subunit S1 encoding gene, predominant in the currently isolated B. pertussis strains, has been found in vaccine strains used for whole-cell pertussis component (wP) production of DTP vaccine in 1960-1978. This outrules the possibility that the appearance of ptxSIA allele might be related to vaccine pressure driven by non-ptxS1A vaccine strains used for long-term immunization with wP. Intranasal challenge animal model testing the efficiency of the clearance of B. pertussis strains harbouring different ptxS1/prn allele gene combinations revealed that currently produced DTwP vaccine may not contain adequate B. pertussis vaccine strains, since isolates with gene variants different from those observed in vaccine strains were eliminated from the lungs of the immunized animals with lower efficiency.

[Genetic variability of Bordetella pertussis strains. Part II. Perspectives]. / Zmiennosc genetyczna szczepów Bordetella pertussis. Czesc II. Perspektywy na przyszlosc.

In some highly immunized countries with long history of pertussis vaccination (The Netherlands, Finland, Poland, USA, France, Great Britain) differences in the DNA patterns and ptxS1 and prn alleles present in B. pertussis strains used for production of pertussis component in the DTP vaccine, in comparison to strains presently isolated from clinical materials have been found. Studies on efficacy of whole-cell and acellular pertussis vaccines in elimination of B. pertussis strains harbouring different gene variants in a particular country might indicate a need for a change of B. pertussis strains used for production of the vaccine against pertussis.