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PubMed1989

Immunization after invasive Haemophilus influenzae type b disease. Serologic response to a conjugate vaccine.

Fifteen children with previous invasive Haemophilus influenzae type b disease were immunized with a Hemophilus-diphtheria toxin mutant protein conjugate vaccine. Serologic responses were compared with those of 31 newly immunized children without previous invasive H influenzae type b disease. Mean levels of antibody to polyribosylribitol phosphate among study children younger than 18 months were 0.086 mg/L before immunization, 0.737 mg/L after first immunization, and 4.453 mg/L after second immunization. In contrast, the comparable mean polyribosylribitol phosphate antibody levels among control children younger than 18 months were 0.107, 3.580, and 63.502 mg/L. A similar pattern of results was found among children aged 18 months or older. Although children with previous invasive H influenzae type b disease do not respond as vigorously to conjugate vaccine as do previously healthy controls, the response is sufficient to justify routine immunization of such children.

Age Factors↗
PubMed1990

Protective efficacy of Haemophilus influenzae type b polysaccharide-diphtheria toxoid-conjugate vaccine.

We estimated the relative protective efficacy of Haemophilus influenzae type b polysaccharide (PRP) vaccine and PRP-diphtheria toxoid-conjugate (PRP-D) vaccine using data from reports of cases of invasive Haemophilus disease occurring in vaccinated children submitted to the Food and Drug Administration, Rockville, Md, and Washington University, St Louis, Mo. During the first 13 months following licensure of each of the vaccines, there were 127 cases reported in recipients of PRP vaccine vs 17 cases in recipients of PRP-D vaccine. The total number of reported cases for each vaccine is not necessarily comparable, since the extent of vaccine use in the population and the extent of reporting of cases may have been different during the two periods. However, the proportion of reported cases occurring equal to or 14 days or more after vaccination (a period considered sufficient to develop immunity) was significantly greater for PRP vaccine (106 [83%] of 127 cases) compared with PRP-D vaccine (7 [41%] of 17 cases). Based on the ratio of late-onset to early-onset cases observed for PRP vaccine, we would have expected 50 late-onset cases after PRP-D vaccination. Since only 7 late-onset PRP-D vaccine failures were reported (86% fewer than expected), the data suggest that PRP-D vaccine was more effective in preventing disease 14 days or more after vaccination than was PRP vaccine.

Bacterial Capsules↗
PubMed1991

Immunization response varies with intensity of acute lymphoblastic leukemia therapy.

Twenty-four children receiving maintenance chemotherapy for acute lymphoblastic leukemia were given booster doses of tetanus-diphtheria combined toxoids. One month later, 19 of the 24 children were given Haemophilus influenzae B oligosaccharide-cross-reacting material conjugate vaccine. Following immunization, all patients had protective antibody titers against tetanus, 92% had protective antidiphtheria titers, and 84% had protective titers against H influenzae. Preimmunization titers, postimmunization titers, and response to immunization varied according to the intensity of therapy. There was no correlation with duration of therapy or quantitative hematologic values in the peripheral blood. These observations support the recommendation that children treated for acute lymphoblastic leukemia should be immunized against H influenzae B.

Antibodies, Bacterial↗
PubMed1991

Response of 7- to 15-month-old infants to sequential immunization with Haemophilus influenzae type b-CRM197 conjugate and polysaccharide vaccines.

OBJECTIVE: To evaluate the immunologic potential of infants 7 to 15 months of age to respond to Haemophilus influenzae type b polysaccharide vaccine following immunization with H influenzae b oligosaccharide-CRM197 conjugate vaccine. STUDY DESIGN: One hundred seventy-one infants, aged 7 to 15 months, were consecutively and alternatively assigned to one of three immunization protocols. Group 1 (n = 71) received three doses of H influenzae b oligosaccharide-CRM197 conjugate vaccine, group 2 (n = 47) received two doses of H influenzae b oligosaccharide-CRM197 conjugate vaccine followed by one dose of H influenzae type b polysaccharide vaccine, and group 3 received one dose of H influenzae b oligosaccharide-CRM197 conjugate vaccine followed by two doses of H influenzae type b polysaccharide vaccine. Immunizations were given on day 0 and at 2 months and 6 months. Anti-H influenzae type b polysaccharide antibody levels were measured on day 0 and 2, 3, 6, 7, and 12 months after the study began. RESULTS: Haemophilus influenzae type b polysaccharide vaccine given as a second dose stimulated an antibody rise but did so less effectively than H influenzae b oligosaccharide-CRM197 conjugate vaccine. Two doses of H influenzae b oligosaccharide-CRM197 conjugate vaccine were highly immunogenic; geometric means were 31 and 35 micrograms/mL in the 7- to 11-month and 12- to 15-month age groups, respectively. Following two doses of H influenzae b oligosaccharide-CRM197 conjugate vaccine, both immunization protocols resulted in (1) equally high geometric mean antibody levels 1 month after immunization and (2) similar geometric mean antibody levels 6 months after immunization. CONCLUSIONS: Haemophilus influenzae b oligosaccharide-CRM197 conjugate vaccine induces antibody levels that would be expected to protect infants from initial invasion and primes the immune system for an anamnestic response. Our data indicate that if a booster immunization is needed, H influenzae type b polysaccharide vaccine could be an alternative to H influenzae b oligosaccharide-CRM197 conjugate vaccine.

Antibodies, Bacterial↗
PubMed1993

Immunogenicity of Haemophilus influenzae type b polysaccharide-tetanus toxoid conjugate vaccine in infants.

OBJECTIVE: To compare the safety and immunogenicity of three investigational lots of Haemophilus influenzae type b polysaccharide-tetanus toxoid (PRP-T) conjugate vaccine in infants. DESIGN: A multicenter, randomized immunogenicity trial. Infants were vaccinated at 2, 4, and 6 months of age with one of three lots of PRP-T. A control group received H influenzae type b oligomers conjugated to CRM197 (HbOC). Serum was obtained before each injection and 1 month after the third dose, and assayed blindly for antibody in one laboratory. SUBJECTS: Four hundred eighty-four infants from private pediatric practices located in five geographic areas. MEASUREMENTS AND RESULTS: There were no significant differences in the number of adverse events reported for infants receiving PRP-T or HbOC, and the rates did not exceed those observed previously in infants given diphtheria-tetanus-pertussis vaccine alone. Total serum anti-PRP antibody responses were analyzed in 336 infants who met strict inclusion criteria. After one, two, or three doses, the respective antibody responses to each of the three lots of PRP-T and to HbOC vaccine were similar. The only exception was one lot of PRP-T, which after one or two injections elicited significantly higher geometric mean antibody responses than the other two lots or the HbOC vaccine. After a third injection, there were no significant lot differences. Combining the data from the different lots, there were no significant differences in the geometric mean antibody concentration after three doses of PRP-T or HbOC (8.3 vs 7.7 micrograms/mL), and 95% and 91%, respectively, of infants had greater than 1.0 microgram/mL of antibody. There were no significant differences in the magnitudes of the respective IgG1-, IgG2-, and IgM-specific antibody concentrations between infants given PRP-T or HbOC. CONCLUSIONS: The three investigational lots of PRP-T tested were safe and were as immunogenic as or more so than the licensed HbOC conjugate vaccine.

Age Factors↗
PubMed2005

Immunological memory: the role of B cells in long-term protection against invasive bacterial pathogens.

Protein-polysaccharide conjugate vaccines that protect against Haemophilus influenzae type b (Hib), serogroup C Neisseria meningitidis, and multiple capsular serotypes of Streptococcus pneumoniae have had a major impact on invasive bacterial disease in childhood when incorporated into routine infant immunization schedules. However, effectiveness data from the United Kingdom suggest that primary infant immunization alone may not be associated with long-term protection. Both immunological priming and antibody persistence are important aspects of long-term protection induced by these vaccines. An improved understanding of the immunobiology of the B-cell response to these vaccines may direct development of immunization strategies that provide sustained protection.

Antibodies, Bacterial↗
PubMed2000

Vaccines for preventing typhoid fever.

BACKGROUND: Whole cell vaccines, consisting of relatively crude preparations of Salmonella typhi administered parenterally, are effective but have a high incidence of adverse effects. Two vaccines have been developed more recently. Ty21a (an attenuated strain of S. typhi administered orally) and Vi (the purified bacterial capsule, given parenterally), have appeared less toxic than the older whole cell vaccines and are thought to be equally effective. OBJECTIVES: The objective of this review was to assess the effects of typhoid fever vaccines. SEARCH STRATEGY: We searched the Cochrane Library, Medline, Index Medicus, Embase and reference lists of articles. SELECTION CRITERIA: Randomised trials comparing typhoid vaccines to other types of vaccine or placebo. DATA COLLECTION AND ANALYSIS: Two reviewers independently assessed trial quality and extracted data. MAIN RESULTS: Seventeen studies, involving nearly two million people, were included. For the whole cell vaccines single dose regimens provided significant protection for the first two years. Two dose regimens provided significant protection for five years. For the Ty21a vaccine, both two and three dose regimens provided statistically significant protection for two years. The three dose regimen provided protection in the third and fourth years, but protection was not statistically significant in the fifth year. The Vi vaccine provided protection for two years, but the protection in the third year was not significant. The three year cumulative efficacy of two doses of whole cell vaccines was 73% (95% confidence interval 65-80), three doses of Ty21a was 51%, (95% confidence interval 35 to 63) and one dose of Vi was 55% (95% confidence interval 30 to 71). Data on adverse effects were limited, but indicate that whole cell vaccines are more toxic than the newer Ty21a and Vi vaccines. REVIEWER'S CONCLUSIONS: The whole cell vaccines provided more prolonged protection than either the Ty21a vaccine or the Vi vaccine. However whole cell vaccines are associated with higher toxicity.

Adolescent↗
PubMed2001

Synthesis of Streptococcus pneumoniae type 3 neoglycoproteins varying in oligosaccharide chain length, loading and carrier protein.

The preparation is described of a range of neoglycoproteins containing synthesised fragments of the capsular polysaccharide of Streptococcus pneumoniae type 3, that is beta-D-GlcpA-(1-->4)-beta-D-Glcp-(1-->O)-(CH2)3NH2 (1), beta-D-Glcp-(1-->3)-beta-D-GlcpA-(1-->4)-beta-D-Glcp-(1-->O)-(CH2)3NH2 (2), and beta-D-GlcpA-(1-->4)-beta-D-Glcp-(1-->3)-beta-D-GlcpA-(1-->4)-beta-D-Glcp-(1-->O)-(CH4)NH2 (3). A blockwise approach was developed for the synthesis of the protected carbohydrate chains, in which the carboxylic groups were introduced prior to deprotection by selective oxidation of HO-6 in the presence of HO-4 by using TEMPO (2,2,6,6-tetramethyl-1-piperidinyloxy radical). After deprotection, the 3-aminopropyl spacer of the fragments was elongated with diethyl squarate (3,4-diethoxy-3-cyclobutene-1,2-dione) and the elongated oligosaccharides were conjugated to CRM197 (cross-reacting material of diphtheria toxin), KLH (keyhole limpet hemocyanin) or TT (tetanus toxoid). The resulting neoglycoconjugates varied in oligosaccharide chain length, oligosaccharide loading and protein carrier. These well-defined conjugates are ideal probes for evaluating the influence of the different structural parameters in immunological tests.

Adjuvants, Immunologic↗
PubMed2006

Mass spectrometric profiling of O-linked glycans released directly from glycoproteins in gels using in-gel reductive beta-elimination.

Glycosylation is a widespread PTM of proteins; the carbohydrate moieties provide various functional, immunological and structural aspects of both eukaryotic and prokaryotic glycoproteins. Traditional strategies used to analyse glycoprotein O-glycans involve glycoprotein isolation, followed by glycan release using solution-phase base-catalysed beta-elimination. However, in a proteomics context, mixtures of proteins and glycoproteins are routinely separated using SDS-PAGE. We have therefore developed a method to enable the profiling of O-linked glycans directly from glycoproteins on gels. This is achieved using in-gel reductive beta-elimination followed by mass spectrometric analysis of the released glycans. Here we describe our demonstration of the feasibility of this approach, our development and optimisation of the procedure using bovine submaxillary gland glycoproteins as a standard, and then show its usefulness by applying the developed procedure to the analysis of the O-glycans from a glycoprotein band from a Coomassie-stained SDS-PAGE separation of a mixture of Mycobacterium avium capsular proteins and glycoproteins. The procedure has been shown to be applicable to both CBB- and silver-stained gels. The method offers a quick and easy way to identify the O-glycans from gel-separated glycoproteins within gel-based proteomics workflows.

Animals↗
PubMed1993

Proportion of protein A bindable molecules in human IgM and IgA antibodies to seven antigens.

Human IgM or IgA antibodies to seven antigens (tetanus and diphtheria toxoids, and five bacterial polysaccharides) were studied by determining what proportion of these antibodies were bound by staphylococcal protein A. This alternative binding is a marker of VH genes of family 3. Each response was studied in an average of nine individuals. The binding proportion of antibodies to the two toxoids resembled that of total serum immunoglobulins; 13-14% of IgA and 40% of IgM antibodies were bound by protein A. All anti-polysaccharide antibodies had higher proportions of protein A bindable molecules than serum IgM or IgA indicating a bias for VH genes. This excess was high in antibodies to Haemophilus influenzae type b (Hib) and pneumococcal type 14 polysaccharides (> two-fold). It was moderate but statistically significant in antibodies to pneumococcal types 18C and 3 capsular polysaccharides and to C polysaccharide. All vaccinated Finns exhibited the VH3-preference in antibodies to Hib and type 14 polysaccharide.

Adult↗
PubMed1994

Comparison of the class-1 outer membrane protein from B:15:P1.16 Neisseria meningitidis strains isolated from patients previously immunized with a serogroup B outer membrane protein vaccine in Norway.

A previous report of a large, double blind, efficacy trial of an experimental Group B meningococcal outer membrane protein vaccine carried out in Norwegian Teenagers, showed a protection rate of 57%. Previous studies had demonstrated the occurrence of mutations in the class-1 outer membrane protein which alter its immunological properties. The occurrence of new mutations might compromise the efficacy of a vaccine and explain the occurrence of any vaccine failures. The porA gene, which encodes expression of the class 1 protein, was sequenced in all isolates from vaccine failures and compared to that of the vaccinating strain H44/76 (B:15:P1.7,16). The porA DNA and deduced amino acid sequences were all identical to that of the vaccinating strain except for that of one isolate which had a sequence identical to strains previously reported in Norway and England with a 'masked P1.7' epitope. The absence of new mutations in the trial was encouraging for the further development of outer membrane protein vaccines.

Adolescent↗
PubMed1996

Evidence for the simultaneous expression of two PspAs by a clone of capsular serotype 6B Streptococcus pneumoniae.

Pneumococcal surface protein A (PspA) has been shown to be a serologically variable virulence factor of Streptococcus pneumoniae. In mice, PspA can elicit antibodies capable of protecting them against otherwise fatal infections with encapsulated pneumococci. In previous studies it has been reported that almost all isolates have two apparently unlinked genomic sequences that are highly homologous to the 5' and 3' halves of Rx1 pspA, although out MAbs to PspA have not detected more than one PspA in any given isolate of S. Pneumoniae. Recently, we have identified four isolates from a clone of capsular serotype 6B pneumococci (MC25-28) that simultaneously express two distinct PspAs. Each of the isolates (MC25-28) exhibited the same two Kpn I fragments (each containing a Hind III site) that hybridized with Rx1 pspA. MAbs specific for PspA detected two PspAs characterized by different molecular weights and different serologic patterns of reactivity (PspA type 6 detected by MAbs XiR278 and 2A4, and PspA type 34 detected only by MAb 7D2) in each of the four isolates. In previous studies XiR278 and 2A4 frequently have been observed to react with PspA epitopes of the same strain. Based on molecular weight data both epitopes were always present on the same molecule. Our present findings raise the possibility that pneumococci make a second serologically variable PspA which is generally not detected by currently available MAbs to PspA.

Antigens, Bacterial↗
PubMed1989

Synthetic peptide representing a T-cell epitope of CRM197 substitutes as carrier molecule in a Haemophilus influenzae type B (Hib) conjugate vaccine.

The cross-reactive material (CRM197) of diphtheria toxin is considered to be advantageous as a carrier molecule in the formulation of a Haemophilus influenzae type b conjugate vaccine. In order to more precisely understand the function of the CRM197 in the vaccine, we have begun mapping the T-cell epitopes of the protein. A peptide which represents a segment of the primary sequence of CRM197 has been identified and found to stimulate diphtheria toxoid or CRM197-primed murine T-lymphocytes. In addition, the peptide is capable of priming T-cells in vivo for a subsequent in vitro T-cell response to itself or to the intact CRM197 molecule. The ability of the peptide to replace CRM197 as a carrier molecule was examined by immunizing mice with PRP, PRP-CRM197 conjugate, or PRP covalently coupled to the peptide. Antibodies to PRP were only detected in the PRP-CRM197 or PRP-peptide immunized groups. Both conjugates elicited primary and secondary antibody responses. Thus, a synthetic peptide representing a defined T-cell epitope of CRM197 has been functionally demonstrated based on its ability to act as a carrier molecule in a PRP conjugate vaccine.

Animals↗