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Query: UMLS:C0348321 (Haemophilus)
 15,372 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Synthetic oligosaccharides derived from the capsular polysaccharide (PRP) of Haemophilus influenzae type b were conjugated to carrier proteins via a thioether linkage. Conjugates were made of trimeric and tetrameric ribose-ribitol-phosphate and tetanus toxoid or diphtheria toxin. All conjugates elicited anti-PRP antibody responses with an increasing immunoglobulin G/immunoglobulin M ratio in adult mice and monkeys. Trimer conjugates elicited lower anti-PRP antibody responses compared with tetramer conjugates. Adult monkeys responded equally well to the tetrameric oligosaccharide-tetanus toxoid conjugate as to the oligosaccharide-CRM197 conjugate (HbOC), which elicits protective levels of serum antibodies in human infants after two or three injections.
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PMID:Synthetic trimer and tetramer of 3-beta-D-ribose-(1-1)-D-ribitol-5-phosphate conjugated to protein induce antibody responses to Haemophilus influenzae type b capsular polysaccharide in mice and monkeys. 156 70

The immunogenicity and safety of a new Haemophilus influenzae type b conjugate vaccine, PRP-T, was studied in 107 infants from the Oxford district. The vaccine was given concurrently with diphtheria, pertussis, tetanus, and polio vaccines at 2, 3, and 4 months of age. Symptoms after immunisation were recorded by a parent. Sera were obtained before the first immunisation and at 5 months of age and the antibodies were measured by both radioimmunoassay and enzyme linked immunosorbent assay (ELISA). No serious adverse reactions were observed and there was no increase in the incidence of expected minor side effects. By radioimmunoassay, the geometric mean titre of serum anticapsular antibody increased from 0.09 micrograms/ml before immunisation to 5.01 micrograms/ml after three immunisations. Ninety eight per cent of children had antibody concentrations consistent with protection (greater than or equal to 0.15 micrograms/ml). IgG antibody concentrations measured by ELISA correlated well with total antibody concentrations measured by radioimmunoassay (r = 0.864). These results provide encouragement that routine immunisation against H influenzae type b at 2, 3, and 4 months of age, could prevent most cases of disease in children in the UK.
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PMID:Immunogenicity and safety of PRP-T conjugate vaccine given according to the British accelerated immunisation schedule. 158 Jun 74

Maternal immunization with the capsular polysaccharide (PRP) vaccine of Haemophilus influenzae type b has been shown to extend the time that protective levels of maternal antibody are detected in infants. In a randomized, blinded trial, PRP or placebo was administered uneventfully to 213 women in the third trimester of pregnancy. Infants born to PRP recipients had significantly higher levels of antibody to PRP than did infants born to placebo recipients: 2.73 micrograms/ml compared with 0.33 microgram/ml. It was estimated that infants of mothers who received the PRP vaccine would be protected for an average of 4 months compared to an average of only 2 months for those of mothers who received placebo. Infants were followed for invasive H. influenzae type b disease through the first year of life; none was detected.
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PMID:Maternal immunization with the capsular polysaccharide vaccine for Haemophilus influenzae type b. 158 47

The first Finnish trial with Haemophilus influenzae type b vaccine was conducted during 1973-1974. It demonstrated that the polysaccharide vaccine was 90% efficacious in children greater than or equal to 18-24 months old. The immunologically superior polysaccharide-protein conjugate vaccines have been used since 1986 in randomized trials. The PRP-D vaccine (polysaccharide conjugated to diphtheria toxoid) was 90% efficacious when given at 3, 4, and 6 months of age to 58,000 infants. In 1988-1989, the PRP-D vaccine was compared with the HbOC vaccine (oligosaccharide conjugated to CRM197 protein). Follow-up is continuing, but both vaccines seem to be efficacious after two doses in infancy.
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PMID:Finnish efficacy trials with Haemophilus influenzae type b vaccines. 158 48

Between February 1988 and June 1990, the safety, immunogenicity, and efficacy of Haemophilus influenzae type b (Hib) oligosaccharide conjugate (HbOC) vaccine was evaluated in a prelicensure trial of 61,080 children. HbOC was found to be safe and immunogenic in infancy. Extended follow-up revealed that as of 31 December 1990, 30 cases of invasive Hib disease had occurred in 74,699 children; 26 were in unvaccinated children and 4 in children who had received only one dose. No disease occurred in children who had received two or three doses. By 30 September 1991, another case had occurred in an unvaccinated child. Comparison of these efficacy data with those of Hib capsular polysaccharide-outer membrane protein conjugate vaccine (PRP-OMP) reveals that both were effective in preventing disease in the first year of life. However, the small cohort in the PRP-OMP study did not allow demonstration of duration of protection beyond 1 year. Ongoing surveillance in larger populations is necessary to allow comparison of the duration of immunity provided by these vaccines.
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PMID:Safety, immunogenicity, and efficacy in infancy of oligosaccharide conjugate Haemophilus influenzae type b vaccine in a United States population: possible implications for optimal use. 158 49

Prospective surveillance of Haemophilus influenzae type b (Hib) disease has been done since 1981 in two high-risk populations, White Mountain Apaches and Navajos. The attack rate in children less than 5 years of age is 5-10 times higher than in the general US population. Three vaccines were evaluated. Unconjugated Hib capsular polysaccharide produced lower antibody responses in 18- and 24-month-old Apache infants than in white infants. HbOC (Hib oligosaccharide covalently linked to the nontoxic mutant diphtheria toxin CRM197) produced low antibody responses in Navajo infants after one or two doses but induced responses similar to those in whites after three doses. The responses of 18-month-old Navajos to HbOC were lower than those of whites, but most achieved protective levels. PRP-OMP (Hib capsular polysaccharide linked to the outer membrane protein complex of Neisseria meningitidis) produced good immune responses in 2-month-old Navajo and Apache infants after a single dose. This vaccine was greater than 90% efficacious in protecting Navajo infants from Hib disease when given at 2 and 4 months of age. Even a single dose achieved a high protective efficacy.
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PMID:Prevention of Haemophilus influenzae type b infections in Apache and Navajo children. 158 50

Since 1987 Haemophilus influenzae b (Hib) conjugate vaccines have been licensed for use in children ages 18 months and older. Before licensure there were no clinical trials of a single dose of any conjugate vaccine in children ages 18 months or older. To fulfill this need we performed an age- and residence-matched case-control study of the efficacy of Hib vaccines. In our study population the protective efficacy (PE) of Hib-diphtheria toxoid conjugate vaccine was 88% (95% confidence interval, 45 to 98%). No vaccine failures were observed with Hib oligosaccharide CRM197 diphtheria protein conjugate vaccine, but usage was not sufficient to establish efficacy: PE = 100% (95% confidence interval, -37 to 100%). The protective efficacy of Hib capsular polysaccharide vaccine was 18% (95% confidence interval -487 to 89%). We conclude that for children ages 18 to 60 months a single dose of the Hib conjugate vaccine, PRP-D, is protective against invasive Hib infections. Consistent with most studies Hib polysaccharide vaccine provided suboptimal protection.
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PMID:Efficacy of Haemophilus influenzae type b vaccines in Massachusetts children 18 to 59 months of age. 163 Aug 57

The capsular polysaccharide from Haemophilus influenzae type b (polyribosyl ribitol-phosphate; PRP) and the capsular polysaccharides from Streptococcus pneumoniae types 6B, 14, 18C, and 23F (Pn6B, Pn14, Pn18C, and Pn23F) were subjected to acid hydrolysis using hydrofluoric (HF) and/or trifluoroacetic acid (TFA) and high-pH anion-exchange chromatography with pulsed amperometric detection in an effort to identify optimum hydrolysis conditions for composition analysis of their carbohydrate components. With the exception of PRP, composition analyses of polysaccharides containing a phosphate moiety in the repeating unit structure (Pn6B, Pn18C, and Pn23F) are significantly improved by subjecting the sample to HF hydrolysis (65 degrees C, 1 h) followed by TFA hydrolysis (98 degrees C, 16 h). This results in essentially quantitative hydrolysis of the phosphodiester bond to the carbohydrate components, which otherwise remained predominantly phosphorylated and poorly accounted for in the analysis. Optimum analysis of PRP was achieved following a 2-h hydrolysis with TFA at 80 degrees C, whereas Pn14 showed optimum results after a 16-h hydrolysis with TFA at 98 degrees C. These analyses also provide information about the relative susceptibility to acid hydrolysis of the various glycosidic and phosphodiester bonds in these polysaccharides, with evidence to suggest that the acid lability of a given bond can be dramatically different from one polysaccharide to another.
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PMID:Carbohydrate composition analysis of bacterial polysaccharides: optimized acid hydrolysis conditions for HPAEC-PAD analysis. 163 23

Haemophilus influenzae type b (Hi b) is responsible for severe invasive infections, particularly meningitis, in children under 5 years of age, with the greatest frequency between 6 and 18 months. The antigenicity of Hib is related to its capsular polysaccharide (polyribosyl-ribitol-phosphate or PRP) which is at the origin of the production of bactericide anti-PRP antibodies. Vaccine using PRP alone have been shown to be well tolerated and immunogenic, but only in children above 2 years of age. We vaccinated 365 infants starting at the age of 3 months with a vaccine using a PRP-tetanus toxoid conjugate (PRP-T), coupled with the DTP pertussis vaccine. Local and general tolerance was found to be very good. Quantitative serum antibody measurements showed excellent immunogenicity. None of the vaccinated infants presented an invasive Hib infection. It therefore appears that early systematic vaccination of infants with PRP-T vaccine should be encouraged.
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PMID:[Evaluation of the vaccination of 3-month-old infants with Haemophilus influenzae type B (Hi b) capsular polysaccharide conjugated to tetanus protein (PRT-T) Pediatric Group of the Lyon Region]. 166 38

Antibodies directed against the capsular polysaccharide (polyribosyl ribitol phosphate [PRP]) or the outer membrane proteins (OMP) of Haemophilus influenzae type b (Hib) promote bactericidal activity, complement 3 (C3) binding, and ingestion by phagocytic cells. To assess the relative contribution of anti-OMP to host defense against Hib, we compared the opsonic activities of anti-PRP and anti-OMP as reflected by the amounts of C3 bound to the bacterial surface. Immunoglobulin G (IgG) fractions containing either anti-PRP or anti-OMP were incubated with Hib in the presence of a C5-deficient complement source. C3, total IgG, and IgG subclasses bound to the bacteria were quantified by enzyme-linked immunosorbent assay. The maximum amount of C3 which could be bound to Hib was greater in the presence of anti-PRP than in the presence of anti-OMP. Also, except at low IgG concentrations, the rate of increase in bound C3 as a function of increasing IgG concentration was greater for anti-PRP than for anti-OMP. Hib-bound anti-OMP consisted primarily of IgG1 and IgG3, whereas bound anti-PRP was primarily IgG1 and IgG2. Thus, the potential for C3 binding to Hib is greater in the presence of anti-PRP than in the presence of anti-OMP, probably because of the larger number of binding sites available to the former. Nonetheless, OMP appear to provide important targets for opsonic antibody and would be logical components of a PRP-conjugate vaccine or may be efficacious as vaccines against nontypeable H. influenzae.
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PMID:Complement component 3 binding to Haemophilus influenzae type b in the presence of anticapsular and anti-outer membrane antibodies. 172 83


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