Interaction of pathogenic neisseriae with nonphagocytic cells.

Nassif, Xavier; So, Magdalene

doi:10.1128/cmr.8.3.376-388.1995

Cited by 3 publications

(1 citation statement)

References 131 publications

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“…Up to 5%-10% of people may be asymptomatic carriers, with the highest rates observed in adolescents and young adults [1,2]. Occasionally, the bacteria crosses the mucosal barrier into the bloodstream, from where it may penetrate the haemato-encephalic barrier, pass through the cerebrospinal fluid and invade the subarachnoid space causing meningococcal meningitis [3][4][5][6]. The bacteria may also multiply in the bloodstream and originate septicaemia or septic shock associated with disseminated intravascular coagulation and cardiovascular failure [7].…”

Section: Introductionmentioning

confidence: 99%

Seroprevalence of meningococcal serogroup C bactericidal antibodies in the Portuguese population, a decade after vaccine introduction in the National Immunisation Programme

et al. 2021

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Background The incidence of invasive meningococcal disease due to serogroup C (MenC) decreased in Portugal since the introduction of the conjugate vaccine (MCC) in the free market in 2001 and in the National Immunisation Plan in 2006. Considering the potential waning of the antibody response reported in the literature, the different vaccination schemes that were used in our country over the past decade, and that Neisseria meningitidis serogroup C continues to circulate, the Portuguese population may currently be at increased risk of infection. In the absence of national data, we evaluated the seroprotection level of the Portuguese population against MenC, in order to identify the protected fraction of the population and ponder on the necessity of a booster dose of the MCC vaccine. Methods We measured serum bactericidal antibody levels against MenC in a representative sample of the population (n = 1500) aged 2–64 years who participated in the 2015/2016 National Serological Survey. Results A total of 31.1% (466/1500, 95%CI: 29–33%) of the individuals studied were protected against MenC. The geometric mean titre was 6.5. The proportion of seroprotected was particularly low in children aged 2–4 years (<16%) who received a single dose of the vaccine at 12 months of age (vaccination strategy since 2012). The proportion of seroprotected was higher (44.7% to 53.5%) in adolescent and young adults (15–24 years of age), resulting from vaccination during the catch-up campaign at 5–15 years of age. The highest protection rates were observed when the vaccine was administered during adolescence. Conclusion The small fraction of population seroprotected, combined with the already known waning effect of the antibody response over time, may indicate that the Portuguese population will become progressively more exposed to the risk of infection. Taking in consideration our results, we recommend to change the current vaccination strategy and introduce a booster dose of the MCC vaccine during adolescence.

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Section: Introductionmentioning

confidence: 99%

Seroprevalence of meningococcal serogroup C bactericidal antibodies in the Portuguese population, a decade after vaccine introduction in the National Immunisation Programme

et al. 2021

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Antigenic variation of gonococcal pilin expression in vivo: analysis of the strain FA1090 pilin repertoire and identification of the pilS gene copies recombining with pilE during experimental human infection The GenBank accession numbers for the sequences reported in this paper are U58840–U58851, U61269, L28978, L28980, L28987 and L28990–L28992.

et al. 2001

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Antigenic variation of gonococcal pilin involves a family of variable genes that undergo homologous recombination, resulting in transfer of variant sequences from the pilS silent gene copies into the complete pilE expression locus. Little is known about the specific recombination events that are involved in assembling new variant pilin genes in vivo. One approach to understanding pilin variation in vivo is to carry out experimental human infections with a gonococcal strain having a fully characterized repertoire of pilin genes, so that the specific recombination events occurring in vivo can be determined. To this end, the authors cloned, sequenced and mapped the pilin genes of strain FA1090 of Neisseria gonorrhoeae. This strain contains one pilE locus and 19 silent gene copies that are arranged in five pilS loci ; the pilE locus and four of the pilS loci are clustered in a 35 kb region of the chromosome. The general features of the pilin loci in FA1090 are similar to those in strain MS11, in which the mechanism of pilin variation has been extensively studied. However, none of the silent copy sequences are identical in the two strains, which emphasizes the extreme variability in this gene family among gonococci. Three male volunteers were inoculated with the same variant of strain FA1090 and developed urethritis within 2-4 d. The pilE gene sequences from a total of 23 colonies cultured from the subjects were analysed, determining which pilS silent copy donated each portion of the expressed pilE genes. There were 12 different pilin variants, one of which was the original inoculum variant, among the in vivo-expressed pilE gene sequences. The pilE of the inoculum variant was derived entirely from a single silent copy (pilS6c1). However, the pilE genes in the majority of the colonies cultured from the infected subjects were chimeras of sequence derived from two or three silent copies. Recombination to generate new pilE sequences involved exchange of single variable minicassettes, multiple minicassettes, entire silent gene copies, or (rarely) recombination within a minicassette.

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Inverse relationship between pilus-mediated gonococcal adherence and surface expression of the pilus receptor, CD46

Tobiason

Seifert

2001

Microbiology

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Pilus-mediated adherence to mucosal epithelial cells is a critical step for Neisseria gonorrhoeae to establish an infection in the human host. CD46, the defined receptor for the gonococcal pilus, is a complement-regulatory protein that is expressed on all human nucleated cells. It was observed that a piliated, Opa N variant of gonococcal strain FA1090 adhered with different efficiencies to the human epithelial cell lines tested (Chang, ME180, HEC-1B and PC-3). Surprisingly, these differences in adherence levels did not correlate with levels of CD46 expressed by these cell lines. In fact, there was an inverse relationship between total surface-exposed CD46 and gonococcal adherence. Four major isoforms of CD46 are produced due to alternative RNA splicing of a surfaceexposed region and the cytoplasmic tail. The relative isoform surface expression of each cell line was determined, and each was found to express different ratios of the four CD46 isoforms. No correlation could be derived between CD46 isoform surface expression and pilus-mediated gonococcal adherence, indicating that CD46 does not act as a classic receptor for gonococcal pili.

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Interaction of pathogenic neisseriae with nonphagocytic cells.

Cited by 3 publications

References 131 publications

Seroprevalence of meningococcal serogroup C bactericidal antibodies in the Portuguese population, a decade after vaccine introduction in the National Immunisation Programme

Seroprevalence of meningococcal serogroup C bactericidal antibodies in the Portuguese population, a decade after vaccine introduction in the National Immunisation Programme

Inverse relationship between pilus-mediated gonococcal adherence and surface expression of the pilus receptor, CD46

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