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Biomedical subjects

J Boslego

Publications and source records attributed to J Boslego.

13 recordsLinked to original sources
PubMed2001

Large scale safety study of a liquid hexavalent vaccine (D-T-acP-IPV-PRP--T-HBs) administered at 2, 4, 6 and 12-14 months of age.

A study was conducted to assess the safety of a new, liquid hexavalent vaccine (Hexavac, Aventis Pasteur MSD, Lyon, France) in a large population of 1783 children in Germany vaccinated at 2, 4, 6 and 12-14 months of age. Immediate reactions, local and systemic reactions, and serious adverse events (SAEs) were monitored. The frequencies of redness > or = 2 cm and swelling > or = 2 cm were 6.7 and 7.1% after all doses of the primary series combined and 13.4 and 12.0% following the booster dose, respectively. Transient swelling of the entire thigh was reported in seven infants after all doses of the primary series (0.1%) and in four children after the booster dose (0.2%). The most frequent systemic adverse events within 3 days after vaccination were irritability (19.3% after primary series and 13.2% after booster) and fever > or = 38.0 degrees C (15.4% after primary series and 28.5% after booster). Fever above 40.0 degrees C was reported in 0.1% of the infants post-primary series and in 0.9% of the children after the booster immunization. Only 3 of 144 SAE were considered to be vaccine related and were seen to resolve spontaneously and without sequelae. The liquid hexavalent vaccine was generally well tolerated when given to children as a primary immunization series at 2, 4 and 6 months and as a booster dose at 12-14 months.

Diphtheria-Tetanus-Pertussis Vaccine↗
PubMed2001

A combined liquid Hib (PRP-OMPC), hepatitis B, diphtheria, tetanus and whole-cell pertussis vaccine: controlled studies of immunogenicity and reactogenicity.

We evaluated the immunogenicity and reactogenicity of a new liquid pentavalent combination vaccine, which incorporates a diphtheria, tetanus and whole-cell pertussis vaccine (DTP) with Hib (PRP-OMPC) and hepatitis B vaccine (HB), in a series of three studies involving 2156 infants. The vaccination schedule was 2, 4, 6 and 18 months for all studies. In addition, subjects in the third study also received a dose of monovalent hepatitis B vaccine at birth. The principal study was a randomised double blind trial of two separate, but concurrently administered vaccines in each of three groups: pentavalent vaccine [DTP-Hib-HB] plus placebo (Group A, n=619); quadrivalent vaccine [DTP-HB] plus Hib vaccine (Group B, n=620); and bivalent vaccine [Hib-HB] plus DTP (Group C, n=226). The second study (Group D, n=231) was an open trial of three separate, but concurrently administered licensed control vaccines (DTP, Hib and HB). The third study (Group E, n=460) administered a dose of monovalent hepatitis B vaccine at birth followed by pentavalent vaccine as for Group A. Subjects were bled prior to the 2- and 18-month vaccinations, and a month after the 6- and 18-month vaccinations. A diary card was used to record subject temperatures and other systemic and local clinical signs for 7 days after each vaccination. The pentavalent vaccine, whether or not preceded by a birth dose of hepatitis B vaccine, was generally well tolerated at all administration times, and had a reactogenicity profile similar to that observed for licensed vaccine controls. Diphtheria and tetanus antibody levels were substantially above protective levels in all study groups. The anti-HBs responses (% > or = 10 mIU/ml) following the 6-month dose of vaccines were, respectively, for Groups A-E: 83.2, 91.7, 96.5, 98.8 and 93.9%, and following the 18-month doses: 87.9, 97.5, 98.8, 98.8 and 92.8%. Anti-PRP responses (% > or = 1.0 microg/ml) following the 6-month dose for Groups A-D were 86.0, 90.5, 91.2, and 74.4%, and after the 18-month dose for Groups A-E were 97.3, 98.3, 98.1, 97.0, and 99.5%. Consistently higher geometric mean titres (GMTs) for pertussis antibodies to agglutinogens (Agg2, Agg3) and pertactin were recorded for the pentavalent vaccine compared to the licensed control vaccine, though they were somewhat lower for pertussigen (PT). Except for the hepatitis B response, antibody responses induced by the pentavalent vaccine to all antigens with a schedule commencing at 2 months of age and completed at 18 months were equivalent to responses to the same antigens induced by the separate, but concurrently administered licensed control vaccines. A regimen of a birth dose of hepatitis B vaccine followed by pentavalent vaccine at 2, 4, 6 and 18 months was not countered by any clinically significant decrease in seroresponses.

Age Factors↗
PubMed1995

Efficacy, safety, and immunogenicity of a meningococcal group B (15:P1.3) outer membrane protein vaccine in Iquique, Chile. Chilean National Committee for Meningococcal Disease.

A meningococcal group B (15:P1.3) outer membrane protein vaccine was tested for efficacy in a randomized, double-blind controlled study in Iquique, Chile. A total of 40 811 volunteers, ages 1-21 years, enrolled in the study. Volunteers received two doses of vaccine six weeks apart by jet injector. Both the experimental vaccine and the control vaccine (Menomune, A, C, Y and W135 meningococcal polysaccharide vaccine) were well tolerated with minor side-effects. Active surveillance for suspected cases of meningococcal disease was conducted for 20 months in Iquique. Eighteen cases of group B meningococcal disease were confirmed during the 20 months. Efficacy was estimated to be 51% (p = 0.11) for all ages combined. In children aged 1-4 no protection was evident, but in volunteers aged 5-21 vaccine efficacy was 70% (p = 0.045). The IgG antibody response by ELISA was characterized by a large booster effect after the second dose, followed by a substantial drop in antibody levels by 6 months. The youngest children had the highest responses. The bactericidal antibody response, on the other hand, was characterized by the lack of a significant booster response, higher responses in the older children, and an increase in the geometric mean titer in the later months of the study in the older children.

Adolescent↗
PubMed1993

Serologic response to Helicobacter pylori among children and teenagers in northern Chile.

The serologic response to Helicobacter pylori was determined in 388 children and teenagers living in Iquique, Chile by using an IgG enzyme-linked immunosorbent assay. Serum antibody levels, as measured by optical density, correlated strongly with age. Increases in the mean antibody level were seen primarily after age five, with rates of seropositivity increasing to > or = 70% among teenagers. The reasons for this age-related pattern of acquisition of infection remain to be determined.

Adolescent↗
PubMed1992

Age-specific prevalence of serum antibodies to the invasion plasmid and lipopolysaccharide antigens of Shigella species in Chilean and North American populations.

Shigella species have virulence plasmids that encode outer membrane proteins (invasion plasmid antigens, Ipa) associated with pathogenicity. Western blots were used to detect antibodies to Ipa in sera from 390 Chilean children, and these responses were compared with those of a US population of infants and adults. Antibodies to lipopolysaccharide (LPS) of Plesiomonas shigelloides and Shigella flexneri 2a were measured by ELISA. Among the Chileans, there was an age-related acquisition of Ipa antibodies, with 28% of 1-year-olds and 100% of children greater than or equal to 10 years showing positive responses. In contrast, none of the US infants and only 38% of the adults had antibodies to Ipa. Levels of LPS antibodies were also found to increase in an age-related manner among the Chileans. These results corroborate findings of previous epidemiologic studies which show that Shigella infections are endemic in Chile, as in other developing countries. The measurement of Ipa and LPS antibodies is a useful seroepidemiologic tool for investigating previous exposure to Shigella species in populations.

Adolescent↗
PubMed1988

Expression of outer membrane protein II by gonococci in experimental gonorrhea.

Gonorrheal urethritis was induced in three males by intraurethral instillation of predominantly pilus+ protein II- gonococci. Virtually all gonococci reisolated from the infected men exhibited protein II+ phenotype. The reisolated gonococci expressed five distinct outer membrane protein II species. Protein IIc+ organisms predominated in urines of all three subjects, but variants expressing this particular protein II were rarely spawned in vitro by input organisms. Protein IIc+ gonococci appeared early in one man's infection; they were joined later by variants that displayed eight other protein II phenotypes, including protein II-. These results show that input protein II- gonococci are supplanted by protein IIc+ variants during incipient gonorrheal urethritis. As infection progresses, a broader variety of protein II+ variants appears.

Bacterial Outer Membrane Proteins↗
PubMed1987

Gonococcal pilin variants in experimental gonorrhea.

When pilus+ Gc were introduced into a male subject's urethra, they gave rise to pilus+ variants whose pilin mRNAs differed from that of input Gc. The differences stemmed from the Gc genome's single complete pilin gene having undergone gene conversion by different partial pilin genes' sequences and by different length stretches of a single partial pilin gene. In some instances, the variant's pilin mRNA appeared to reflect two independent gene-conversion events that used sequences from two different partial pilin genes. The resulting variants' pilins exhibited antigenic differences compared with the pilin polypeptide of input Gc; these differences were discernible by immunoblotting with mAbs. Amino acid and antigenic changes occurred in a segment of the variants' pilin polypeptides that previously was thought to be conserved or constant in sequence.

Amino Acid Sequence↗
PubMed1987

Human bactericidal antibody response to meningococcal outer membrane protein vaccines.

Several different meningococcal outer membrane protein vaccines have been prepared and used in human safety and immunogenicity studies. The results of these studies have led to some general conclusions regarding the human antibody response to these vaccines. A review of these conclusions, however, indicates that a number of important questions and problems still need to be addressed. Two of these are the determination of the protective level of bactericidal antibody in human serum and the impact of phase variation of surface antigens on vaccine strategy. Bactericidal assays using intrinsic complement and high concentrations of serum suggest that the level of natural immunity to group B meningococci is quite high, but is increased by vaccination with outer membrane protein vaccine. Phase variation in meningococcal surface antigens including capsule, class 1 protein, class 5 protein, and lipopolysaccharide was demonstrated using colony blotting with monoclonal antibodies. Phase variation resulted in differences in susceptibility to the bactericidal activity of human sera.

Antibodies, Bacterial↗
PubMed1987

Gene conversion accounts for pilin structural changes and for reversible piliation "phase" changes in gonococci.

Pilus+ "wild-type" gonococci (Gc) frequently display gene conversion of their expressed complete pilin gene (CPG); a copy of DNA derived from one of the Gc genome's multiple silent partial pilin genes (PPG) is recombinationally-inserted into the CPG's central and 3' portions with formation of a new, chimeric CPG. Expression of that new CPG leads to either 1) retention of pilus+ phenotype but change in pilin primary structure/antigenicity, or 2) phase change to pilus- phenotype capable of reverting. This study utilizes pilus revertants of P-rp +/- Gc and P+ colony morphotype variants spawned by P++ Gc to examine pilin gene conversion in strain MS11mk Gc in greater detail. Each revertant's and variant's expressed pilin gene's sequence (as pilin mRNA) was defined to learn whether their differences are due to gene conversion by different PPGs, or by varying stretches from the same PPG, or both. Gene conversion by PPG pilS1 copy 2 has been documented in Gc recovered from a human volunteer's urethra previously inoculated with pilus Gc (strain MS11). The pilus+ Gc isolated expressed structurally/antigenically distinct pilins.

Amino Acid Sequence↗
PubMed1987

Analyses of the immunoaccessibility of H8 antigen and the functionality of H8 specific monoclonal antibody 10.

The immunoaccessibility of the H8 antigen was examined as was the functionality of H8 specific monoclonal antibody (McAb 10). Immunoaccessibility of H8 varied among individual gonococci grown in vitro; the overall degree of variability was strain dependent. The H8 antigen was detected on the surface of most but not all gonococci found in urine sediment from an infected volunteer. The H8 specific McAb 10 was not bactericidal for strains of serum resistant gonococci; in the serum sensitive strain, an increase of approximately .5 logs above the bactericidal activity of antibody depleted normal human serum was observed. It is possible that the apparent paradox of the common, immunogenic, antigenic surface constituent H8 may be resolved in part by variation in immunoaccessibility within and among gonococcal strains.

Antibodies, Bacterial↗
PubMed1980

Antigenic specificity of antibodies in vaginal secretions during infection with Neisseria gonorrhoeae.

Antibodies in genital secretions of patients with gonorrhea have been shown to inhibit the attachment of gonococci to epithelial cells. The gonococcal antigens for which these antibodies are specific were studied by adsorption of the genital secretions from a patient infected with gonorrhea with purified lipopolysaccharide, outer membrane complex, or purified pili of homologous Neisseria gonorrhoeae and measurement of the reduction of inhibition of attachment of the gonococci to epithelial cells. The removal of antibodies was documented with the use of a solid-phase radioimmunoassay in which the amount of antibody in the adsorbed secretions that bound to a specific gonococcal antigen was shown to be reduced as compared with the amount of antibody in unadsorbed secretions. The antibody in the secretions that inhibited attachment was removed primarily by adsorption with the homologous pili, not with homologous lipopolysaccharide. A preparation of the homologous outer membrane complex that contained pili, cell-wall proteins, and lipopolysaccharide also blocked the inhibitory antibody.

Adsorption↗