Bordetella pertussis Strain Lacking Pertactin and Pertussis Toxin.
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ABSTRACT:
SUBMITTER: Williams MM
PROVIDER: S-EPMC4734536 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:Recent reemergence of pertussis (whooping cough) in highly vaccinated populations and rapid expansion of Bordetella pertussis strains lacking pertactin (PRN), a common acellular vaccine antigen, have raised the specter of vaccine-driven evolution and potential return of what was once the major killer of children. The discovery that most circulating B. pertussis strains in the United States have acquired new and independent disruptive mutations in PRN is compelling evidence of strong selective pressure. However, the other 4 antigens included in acellular vaccines do not appear to be selected against so rapidly. We consider 3 aspects of PRN that distinguish it from other vaccine antigens, which might, individually or collectively, explain why only this antigen is being precipitously eliminated. An understanding of the increase in PRN-deficient strains should provide useful information for the current search for new protective antigens and provide broader lessons for the design of improved subunit vaccines.
| S-EPMC8153889 | biostudies-literature
Project description:BACKGROUND:Acellular Pertussis vaccines against whooping cough caused by Bordetella pertussis present a much-improved safety profile compared to the original vaccine of killed whole cells. The principal antigen of acellular Pertussis vaccine, Pertussis Toxin (PT), must be chemically inactivated to obtain the corresponding toxoid (PTd). This process, however, results in extensive denaturation of the antigen. The development of acellular Pertussis vaccines containing PTd or recombinant PT (rPT) with inactivated S1, Filamentous Hemagglutinin (FHA), and Pertactin (PRN) has shown that the yield of PRN was limiting, whereas FHA was overproduced. To improve antigen yields and process economics, we have constructed strains of Bordetella pertussis that produce enhanced levels of both rPT and PRN. RESULTS:Three recombinant strains of Bordetella pertussis were obtained by homologous recombination using an allelic exchange vector, pSS4245. In the first construct, the segment encoding PT subunit S1 was replaced by two mutations (R9K and E129G) that removed PT toxicity and Bp-WWC strain was obtained. In the second construct, a second copy of the whole cluster of PT structural genes containing the above mutations was inserted elsewhere into the chromosome of Bp-WWC and the Bp-WWD strain was obtained. This strain generated increased amounts of rPT (3.77 ± 0.53 ?g/mL) compared to Bp-WWC (2.61 ± 0.16 ?g/mL) and wild type strain (2.2 ?g/mL). In the third construct, a second copy of the prn gene was inserted into the chromosome of Bp-WWD to obtain Bp-WWE. Strain Bp-WWE produced PRN at 4.18 ± 1.02 ?g/mL in the cell extract which was about two-fold higher than Bp-WWC (2.48 ± 0.10 ?g/mL) and Bp-WWD (2.31 ± 0.17 ?g/mL). Purified PTd from Bp-WWD at 0.8-1.6 ?g/well did not show any toxicity against Chinese hamster ovary (CHO) cell whereas purified PT from WT demonstrated a cell clustering endpoint at 2.6 pg/well. CONCLUSIONS:We have constructed Bordetella pertussis strains expressing increased amounts of the antigens, rPT or rPT and PRN. Expression of the third antigen, FHA was unchanged (always in excess). These strains will be useful for the manufacture of affordable acellular Pertussis vaccines.
| S-EPMC3349578 | biostudies-literature
Project description:There is evidence that pertussis is reemerging in vaccinated populations. We have proposed, and provided evidence for, one explanation for this phenomenon in The Netherlands: antigenic divergence between vaccine strains and circulating strains. Finland has a pertussis vaccination history very similar to that of The Netherlands, and yet there is no evidence for an increase in the incidence of pertussis to the extent that it was observed in The Netherlands. A comparison of the Bordetella pertussis strains circulating in the two countries may shed light on the differences in pertussis epidemiology. Here we investigated whether temporal changes had occurred in pertussis toxin and pertactin types produced by the Finnish B. pertussis population. We show that strains isolated before 1964 produced the same pertussis toxin and pertactin variants as the vaccine strains. However, these vaccine types were replaced in later years, and in the 1990s most strains were distinct from the vaccine strains with respect to the two proteins. These trends are similar to those found in the Dutch B. pertussis population. An interesting difference between the contemporary Finnish and Dutch B. pertussis populations was found in the frequencies of pertactin variants, possibly explaining the distinct epidemiology of pertussis in the two countries.
| S-EPMC96632 | biostudies-literature
Project description:Bordetella pertussis not expressing pertactin has increased in countries using acellular pertussis vaccines (ACV). The deficiency is mostly caused by pertactin gene disruption by IS481. To assess the effect of the transition from whole-cell vaccine to ACV on the emergence of B. pertussis not expressing pertactin in Spain, we studied 342 isolates collected during 1986-2018. We identified 93 pertactin-deficient isolates. All were detected after introduction of ACV and represented 38% of isolates collected during the ACV period; 58.1% belonged to a genetic cluster of isolates carrying the unusual prn::del(-292, 1340) mutation. Pertactin inactivation by IS481 insertion was identified in 23.7% of pertactin-deficient isolates, arising independently multiple times and in different phylogenetic branches. Our findings support the emergence and dissemination of a cluster of B. pertussis with an infrequent mechanism of pertactin disruption in Spain, probably resulting from introduction of ACV.
| S-EPMC9045434 | biostudies-literature
Project description:Pertactin is an outer membrane protein expressed by Bordetella pertussis, Bordetella parapertussis, and Bordetella bronchiseptica that induces protective immunity to Bordetella infections. The immunodominant and immunoprotective epitopes of pertactin include two repeated regions, I and II. Comparison of these two repeated regions showed that B. parapertussis pertactin is invariant, whereas B. pertussis pertactin varies mostly in region I and B. bronchiseptica pertactin varies in both repeated regions I and II, but mostly in region II. These differences may result from specific characteristics of these Bordetella species.
| S-EPMC98445 | biostudies-literature
Project description:Acellular vaccines against Bordetella pertussis were introduced in Australia in 1997. By 2000, these vaccines had replaced whole-cell vaccines. During 2008-2012, a large outbreak of pertussis occurred. During this period, 30% (96/320) of B. pertussis isolates did not express the vaccine antigen pertactin (Prn). Multiple mechanisms of Prn inactivation were documented, including IS481 and IS1002 disruptions, a variation within a homopolymeric tract, and deletion of the prn gene. The mechanism of lack of expression of Prn in 16 (17%) isolates could not be determined at the sequence level. These findings suggest that B. pertussis not expressing Prn arose independently multiple times since 2008, rather than by expansion of a single Prn-negative clone. All but 1 isolate had ptxA1, prn2, and ptxP3, the alleles representative of currently circulating strains in Australia. This pattern is consistent with continuing evolution of B. pertussis in response to vaccine selection pressure.
| S-EPMC3966384 | biostudies-literature
Project description:Prevalence of pertactin-lacking Bordetella pertussis isolates has been observed worldwide. In Japan, however, we found that the frequency of pertactin-deficient isolates in 2014-2016 (8%) was significantly lower than the frequency in 2005-2007 (41%), 2008-2010 (35%), and 2011-2013 (25%). This reduction was closely associated with changes in genotypes.
| S-EPMC5367402 | biostudies-literature
Project description:Studies performed in several countries have demonstrated the recent emergence and subsequent dominance of circulating Bordetella pertussis strains harboring pertactin and pertussis toxin variants not included in pertussis vaccines. Determination of the pertactin gene variants is commonly performed using a time-consuming and expensive sequence analysis. We developed a simple and reliable pertactin typing algorithm suitable for large-scale screening. The assay correctly identified all pertactin alleles in representative strains. The typing of 231 clinical strains of B. pertussis routinely isolated in Belgium showed that this algorithm was adequate to identify less-frequent prn types like prn9 and prn11.
| S-EPMC387558 | biostudies-literature
Project description:The reemergence of pertussis has been reported in several countries despite high vaccination coverage. Studies in The Netherlands and Finland have investigated polymorphism in the genes coding for two important virulence factors of Bordetella pertussis, pertactin and pertussis toxin, and identified the emergence and subsequent dominance in circulating strains of pertactin and toxin variants not found in the whole-cell vaccine (WCV). The study described here investigated whether such variation had occurred in the United Kingdom, which presently has low levels of pertussis. Sequence analysis of the genes for pertactin (prnA) and the pertussis toxin S1 subunit (ptxA) among isolates of B. pertussis from 285 United Kingdom patients, from 1920 to 1999, revealed three prnA variants, prnA(1), prnA(2), and prnA(3), and two ptxA variants, ptxA(1) and ptxA(2), showing differences in nucleic acid sequence. The proportion of pertactin gene types not included in the United Kingdom WCV, i.e., prnA(2) and prnA(3), has increased in recent years and was found in 21 of 86 (24%) strains from the 1980s and 56 of 105 (53%) strains from the 1990s. To date, the presence of these nonvaccine prnA types has not been associated with a resurgence of pertussis in the United Kingdom. The distribution of prnA and ptxA types in The Netherlands, Finland, and the United Kingdom in the 1990s is distinct. The most striking difference in the United Kingdom isolates is that all 105 of the most recent circulating strains (from 1998 to 1999) are of a pertussis toxin type found in the United Kingdom WCV, i.e., ptxA(1).
| S-EPMC98665 | biostudies-literature
Project description:The adhesin pertactin (Prn) is one of the major virulence factors of Bordetella pertussis, the etiological agent of whooping cough. However, a significant prevalence of Prn-deficient (Prn(-)) B. pertussis was observed in Japan. The Prn(-) isolate was first discovered in 1997, and 33 (27%) Prn(-) isolates were identified among 121 B. pertussis isolates collected from 1990 to 2009. Sequence analysis revealed that all the Prn(-) isolates harbor exclusively the vaccine-type prn1 allele and that loss of Prn expression is caused by 2 different mutations: an 84-bp deletion of the prn signal sequence (prn1?SS, n = 24) and an IS481 insertion in prn1 (prn1::IS481, n = 9). The frequency of Prn(-) isolates, notably those harboring prn1?SS, significantly increased since the early 2000s, and Prn(-) isolates were subsequently found nationwide. Multilocus variable-number tandem repeat analysis (MLVA) revealed that 24 (73%) of 33 Prn(-) isolates belong to MLVA-186, and 6 and 3 Prn(-) isolates belong to MLVA-194 and MLVA-226, respectively. The 3 MLVA types are phylogenetically closely related, suggesting that the 2 Prn(-) clinical strains (harboring prn1?SS and prn1::IS481) have clonally expanded in Japan. Growth competition assays in vitro also demonstrated that Prn(-) isolates have a higher growth potential than the Prn(+) back-mutants from which they were derived. Our observations suggested that human host factors (genetic factors and immune status) that select for Prn(-) strains have arisen and that Prn expression is not essential for fitness under these conditions.
| S-EPMC3279416 | biostudies-literature