Fcgamma receptor polymorphisms determine the magnitude of in vitro phagocytosis of Streptococcus pneumoniae mediated by pneumococcal conjugate sera.
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Fcgamma receptors show two genetically determined polymorphisms: the biallelic FcgammaRIIa-R131 and -H131 polymorphism and the NA1/NA2 FcgammaIIIb polymorphism. Using 10 pre- and postconjugate vaccination sera from adults, we analyzed in vitro phagocytic capacities of three different combinations of polymorphonuclear leukocyte FcgammaR allotypes: those homozygous for the H131 and NA1 allotype, those homozygous for the R131 and NA2 allotype, and those heterozygous for both receptors. For pre- and postvaccination sera, mean phagocytosis levels for the homozygous H131/NA1 allotype were 4 -fold higher than for the homozygous R131/NA2 allotype. There was a strong and significant correlation between IgG2 ELISA antibody titers and phagocytosis levels for the homozygous H131/NA1 Fcgamma receptor allotype and the heterozygous allotype but not for the homozygous R131/NA2 allotype. There was no relation between IgG1 ELISA titer and phagocytosis level. Apparently the IgG2 antibodies induced are functionally the most important. This may explain the large effect of Fcgamma receptor polymorphisms on in vitro phagocytosis of pneumococci mediated by conjugate antisera. (+info)
Synthesis and preclinical evaluation of glycoconjugate vaccines against group B Streptococcus types VI and VIII.
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Group B Streptococcus (GBS) types VI and VIII are prevalent among serotypes isolated from pregnant women in Japan. Maternal vaccination with a safe and effective GBS vaccine has been proposed as a rational approach to prevent neonatal GBS disease. Because antibody specific for the capsular polysaccharide (CPS) antigens of GBS is protective, vaccines were developed with purified type VI and VIII CPS coupled to tetanus toxoid. In rabbits the newly synthesized conjugate vaccines elicited high-titered, type-specific antibody that was opsonically active in vitro. Moreover, litters born to mice actively vaccinated with the conjugate vaccines, in contrast to uncoupled CPS or saline, were protected against an ordinarily lethal challenge of GBS of homologous serotype. GBS types VI and VIII conjugate vaccines of the design presented may be important components of a multivalent GBS vaccine for use in regions where these serotypes predominate. (+info)
Activation of human monocytic cells by Borrelia burgdorferi and Treponema pallidum is facilitated by CD14 and correlates with surface exposure of spirochetal lipoproteins.
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Here we examined the involvement of CD14 in monocyte activation by motile Borrelia burgdorferi and Treponema pallidum. B. burgdorferi induced secretion of IL-8 by vitamin D3-matured THP-1 cells, which was inhibited by a CD14-specific mAb known to block cellular activation by LPS and the prototypic spirochetal lipoprotein, outer surface protein A. Enhanced responsiveness to B. burgdorferi also was observed when THP-1 cells were transfected with CD14. Because borreliae within the mammalian host and in vitro-cultivated organisms express different lipoproteins, experiments also were performed with "host-adapted" spirochetes grown within dialysis membrane chambers implanted into the peritoneal cavities of rabbits. Stimulation of THP-1 cells by host-adapted organisms was CD14 dependent and, interestingly, was actually greater than that observed with in vitro-cultivated organisms grown at either 34 degrees C or following temperature shift from 23 degrees C to 37 degrees C. Consistent with previous findings that transfection of Chinese hamster ovary cells with CD14 confers responsiveness to LPS but not to outer surface protein A, B. burgdorferi failed to stimulate CD14-transfected Chinese hamster ovary cells. T. pallidum also activated THP-1 cells in a CD14-dependent manner, although its stimulatory capacity was markedly less than that of B. burgdorferi. Moreover, cell activation by motile T. pallidum was considerably less than that induced by treponemal sonicates. Taken together, these findings support the notion that lipoproteins are the principle component of intact spirochetes responsible for monocyte activation, and they indicate that surface exposure of lipoproteins is an important determinant of a spirochetal pathogen's proinflammatory capacity. (+info)
The epidemiological impact of antimeningococcal B vaccination in Cuba.
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The incidence of invasive meningococcal disease (IMD) before (1984-1988) and after (1989-1994), a nationwide intervention with VA-MENGOC-BC vaccination started in 1989, was compared. The prevaccination period incidence density (ID> 8.8/10(5) year-person) was higher than the postvaccination ID (ID< 6.5/10(5) year-person). The percentage proportional differences from the start to the end of each period of ID in the vaccinal period was higher (87%) than the prevaccinal (37%) with significant differences among vaccinated groups (< 25 years old). A break-point (Chow test) was confirmed by the decrease in the ID between 1989 and 1990 in children under 1 year old, 5-9, 10-14, 15-19 and 50-54 years. Comparison of ID using maps showed a decrease in IMD in all municipalities during the postvaccination period. These findings support the epidemiological impact of VA-MENGOC-BC vaccination in the reduction of IMD morbidity. (+info)
Phenotypic and genetic characterization of a novel Borrelia burgdorferi sensu lato isolate from a patient with lyme borreliosis.
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Borrelia burgdorferi sensu lato A14S was cultured from a skin biopsy specimen of a patient with erythema migrans in The Netherlands. This isolate had a unique DNA fingerprint pattern compared to 135 other B. burgdorferi sensu lato isolates. In this study, the isolate A14S was further characterized by protein analysis with sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and reactivity with various monoclonal antibodies. In addition, the 16S rRNA, ospA, and ospC genes, as well as the 5S-23S rRNA intergenic spacer DNA, were amplified by PCR, cloned, and sequenced. SDS-PAGE protein profiles and phylogenetic analysis based on all of the analyzed genes confirmed that B. burgdorferi sensu lato A14S was phenotypically and genetically different from the three human pathogenic species B. burgdorferi sensu stricto, Borrelia garinii, and Borrelia afzelii, as well as from other B. burgdorferi sensu lato species. Our findings indicate that Borrelia genomic groups or isolates other than the three well-known human pathogenic species may also cause human Lyme borreliosis. (+info)
Alternative vaccination schedules (0, 1, and 6 months versus 0, 1, and 12 months) for a recombinant OspA Lyme disease vaccine.
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We have compared the immunogenicity profile of a recombinant lipoprotein outer-surface protein A (OspA) Lyme disease vaccine administered on schedules of 0, 1, and 6 months (group 1) or 0, 1, and 12 months (group 2) to 800 healthy subjects, aged 15-50 years. One month after the second dosing, geometric mean titers of IgG antibodies to OspA were 1,309 ELISA units (EL.U)/mL in group 1 and 1,404 EL.U/mL in group 2. One month after the third dosing, the titers were 7,205 EL.U/mL and 10,659 EL.U/mL, respectively. Using bioequivalence methodology, we showed that the two vaccination schedules elicit an equivalent immune response 1 month after administration of dose 3: at that point, 91%-93% of all subjects had titers > or =1,400 EL.U/mL, proposed to be protective for one tick season. The vast majority of local and systemic symptoms were mild to moderate and of limited duration. The 0, 1, and 6 months vaccination schedule is a viable alternative to the 0, 1, and 12 months schedule and can provide protection against Lyme disease during one tick season. (+info)
A 20-year epidemiological study of pneumococcal meningitis.
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We conducted a retrospective analysis of 55 community-acquired Streptococcus pneumoniae meningitis illnesses in Huntington, West Virginia, from 1978 to 1997. Fourteen (36.8%) of 38 adults and 2 (11.8%) of 17 children died. Serotypes 6, 23, 3, and 18 accounted for 20 (41.7%) of 48 strains available for serotyping. Of 40 strains available for antimicrobial susceptibility testing, 1 serotype 19 and 1 serotype 23 strain showed intermediate resistance and a second serotype 23 strain showed high resistance to penicillin; all three patients survived. The case-fatality rates among adults who received penicillin alone, gentamicin in combination, or vancomycin and cephalosporin together were 57.1%, 55.5%, and 60%, respectively, and among those who received chloramphenicol or a third-generation cephalosporin, they were 11.1% or nil, respectively. No child died who received chloramphenicol or vancomycin. Two (33%) of 6 children died who received a third-generation cephalosporin; both were critically ill when initially treated. No child and one adult had received pneumococcal vaccine prior to becoming ill. (+info)
Cutting edge: inflammatory signaling by Borrelia burgdorferi lipoproteins is mediated by toll-like receptor 2.
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The agent of Lyme disease, Borrelia burgdorferi, produces membrane lipoproteins possessing potent inflammatory properties linked to disease pathology. The recent association of toll-like receptors (TLR) 2 and 4 with LPS responses prompted the examination of TLR involvement in lipoprotein signaling. The ability of human cell lines to respond to lipoproteins was correlated with the expression of TLR2. Transfection of TLR2 into cell lines conferred responsiveness to lipoproteins, lipopeptides, and sonicated B. burgdorferi, as measured by nuclear translocation of NF-kappaB and cytokine production. The physiological importance of this interaction was demonstrated by the 10-fold greater sensitivity of TLR2-transfected cells to lipoproteins than LPS. Futhermore, TLR2-dependent signaling by lipoproteins was facilitated by CD14. These data indicate that TLR2 facilitates the inflammatory events associated with Lyme arthritis. In addition, the widespread expression of lipoproteins by other bacterial species suggests that this interaction may have broad implications in microbial inflammation and pathogenesis. (+info)