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

Rapid diagnosis of Haemophilus influenzae type b meningitis is possible using immunological tests for capsular antigen (polyribophosphate, PRP), such as countercurrent immunoelectrophoresis (CIE) and latex particle agglutination (LPA). We compared two tests in monkeys with evolving, serially quantitated H. influenzae type b bacteremia (n = 23) and meningitis (n = 21). In vitro, the LPA test was sensitive to 0.5 ng of PRP/ml of saline, and the CIE test was sensitive to 1.0 ng/ml; in serum, however, CIE detected 5.0 ng of PRP/ml, whereas the sensitivity of LPA was unchanged. LPA detected PRP earlier in the course of bacteremia (mean, 12 h after onset; range, 4 to 36 h) than did CIE (mean, 45 h; range, 4 to 168 h) (P less than 0.01). A positive LPA test required greater than or equal to 100 bacteria per ml of blood, whereas CIE required greater than or equal to 1,000/ml. PRP accumulated with continuing blood stream infection, aiding detection of low-grade bacteremia. LPA detected antigen in cerebrospinal fluid (CSF) earlier in the course of meningitis and at a lower bacteria density than did CIE. Both methods detected antigen reliably with greater than or equal to 1,000 bacteria per ml of CSF. A close correlation existed between CSF concentrations of capsular antigen and bacteria (r = 0.90, P less than 0.001). We conclude that the LPA method permits earlier diagnosis of H. influenzae type b infection in part because of its greater sensitivity.
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PMID:Comparison of two antigen detection techniques in a primate model of Haemophilus influenzae type b infection. 11 34

Mortality from meningitis caused by Haemophilus influenzae type b (Hib), a disease that affects mainly infants and young children, can reach 5% in industrialised countries and ten times that in non-industrialised countries. To determine the efficacy of vaccination against Hib, we carried out a retrospective survey of the incidence of Hib meningitis over five decades in the Greater Helsinki area of Finland, where all children with bacterial meningitis are treated in one of three centres. Except for a meningococcal epidemic in the early 1970s, Hib was the leading cause of childhood bacterial meningitis until the Hib conjugate vaccines changed the picture profoundly. In 1986-87 the polysaccharide-diphtheria toxoid conjugate (PRP-D) was given experimentally to 50% of infants. In 1988-89 all infants were vaccinated, 50% with PRP-D, 50% with another conjugate vaccine, the oligosaccharide-CRM197 protein conjugate (HbOC). Since 1990 a third conjugate vaccine, the polysaccharide-tetanus toxoid (PRP-T), has been administered routinely to all infants. The vaccines were administered at age 3-6 months, with a booster dose at 14-18 months. In the first 5 years of the Hib vaccination programme the number of cases of Hib meningitis in children aged 0-4 years fell sharply, from 30 in 1986 (the first year of the programme) to none in 1991. The decline contrasts sharply with the rising trend up to the mid 1980s. Vaccination seems to be the only explanation for the observed change in the epidemiology of Hib meningitis.
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PMID:Rapid disappearance of Haemophilus influenzae type b meningitis after routine childhood immunisation with conjugate vaccines. 135 65

PRP-meningococcal outer membrane protein complex (PRP-OMPC) and oligosaccharide linked to variant diphtheria toxin (HbOC) Haemophilus influenzae type b (HIB) conjugate vaccines have both been licensed for United States infants at 2 months of age. Differences in serologic responses for these vaccines have been noted with PRP-OMPC producing an early response at 2 months of age and HbOC producing a higher response after a third dose at 6 months of age. To further characterize the nature of these distinct responses, we measured the IgG1, IgG2 and IgM anti-HIB concentrations by enzyme-linked immunosorbent assay after administration of both vaccines. PRP-OMPC produced an IgM and IgG1 anti-HIB response following the initial dose at 2 months of age. After two doses of HbOC an increase in IgG1 and IgM were noted and after a third dose at 6 months of age an IgG2 anti-HIB response occurred. In addition 33 study subjects were boosted with PRP-OMPC at age 18 months and compared with 34 subjects who received only a primary dose. The anti-HIB IgG1 and IgG2 concentrations following the booster dose were both significantly higher for the primed group (P = 0.0001 and P = 0.001, respectively). Both HIB conjugate vaccines produce predominantly IgG1 anti-HIB antibody responses. The early response to PRP-OMPC vaccine at 2 months of age may result from adjuvant characteristics of the OMPC.
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PMID:IgG1, IgG2 and IgM responses to two Haemophilus influenzae type b conjugate vaccines in young infants. 140 86

Haemophilus influenzae type b polysaccharide-conjugate vaccines elicit protective antibody responses in young infants. One of these conjugates, polysaccharide linked to outer membrane protein complex (PRP-OMPC), is produced by linking the capsular polysaccharide to an outer membrane protein complex derived from group B Neisseria meningitidis. The outer membrane protein complex contains T cell carrier epitopes that elicit T cell-dependent antibody responses. OMPC also has been shown to increase the antibody response to other proteins administered concurrently that are not covalently linked (i.e., acts as an adjuvant). In this study PRP-OMPC immunized mice demonstrated significant increases in spleen size as well as in splenocyte number as compared to saline controls (p < 0.01, p < 0.001, respectively). No such increase was noted after immunization with another H. influenzae type b-conjugate vaccine, oligosaccharide linked to a variant of diphtheria toxin. By analytic flow cytometry, the mice immunized with PRP-OMPC demonstrated an increase in large splenocytes expressing the Ag Mac-1 (CD11b, CR3). Furthermore, the spleens on histologic examination were characterized by an increase in the red pulp area consisting predominantly of cells of macrophage morphology. By immunohistochemical staining, the cells were identified as macrophages due to expression of Mac-1 and p150,95 (CD11C) Ag. After PRP-OMPC immunization, severe combined immunodeficient mice also demonstrated significant splenomegaly with an increase in macrophages identified by expression of Mac-1 and MHC class II Ag. Thus PRP-OMPC vaccine resulted in T cell-independent splenomegaly with an increase number of macrophages. We propose that this unique property may confer increased immunogenicity to PRP-OMPC through macrophage activation and cytokine release. Furthermore, the effect on macrophages may explain the "adjuvant" capacity of OMPC.
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PMID:Effect of Haemophilus influenzae polysaccharide outer membrane protein complex conjugate vaccine on macrophages. 146 Feb 86

Routine immunisation of infants against Haemophilus influenzae type b (Hib) has the potential to prevent up to 1200 cases of serious infection and 60 deaths every year in the United Kingdom. Sara Hodgson reports the findings of a study in the Oxford region to determine the safety and immunogenicity of the Hib conjugate vaccine PRP-T when given to British infants in concurrence with primary immunisations, according to the accelerated schedule of two, three and four months of age.
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PMID:Primary prevention of haemophilus influenzae type b. 146 45

A simplified enzyme-linked immunospot (ELISPOT) technique is described for the detection of cells secreting antibodies to tetanus toxoid (TT), diphtheria toxoid (DT) or Haemophilus influenzae type b capsular polysaccharide (PRP). By combining the cell suspension with the enzyme-linked secondary antibodies in one incubation, the second incubation and washing procedure could be omitted from the original technique. The simplified assay had the same sensitivity for anti-TT and anti-DT spot-forming cells as the ordinary ELISPOT assay. The IgG anti-PRP spots were, however, improved both in quality and in quantity (median: 40% more spots), while the detection of IgM and IgA anti-PRP spot-forming cells was the same in the two techniques. This simplified technique can probably also be used to save time in other antigen systems and should be considered when designing ELISPOT assays for the detection of polysaccharide-specific antibody-secreting cells.
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PMID:A simplification of the enzyme-linked immunospot technique. Increased sensitivity for cells secreting IgG antibodies to Haemophilus influenzae type b capsular polysaccharide. 147 56

A study on natural immunity to Haemophilus influenzae type b (Hib) was carried out in the province of Siena on 474 subjects ranging in age from 3 days to 70 years. The titration of antibody to capsular polysaccharide (PRP) was performed by the radioantigen-binding assay (RABA) method. A total of 66.67% of the population studied presented an antibody level considered to be protective (greater than or equal to 0.15 microgram ml-1). Seropositivity was 5.7% in the 5-7 month age group and 29.09% in the 8-17 month age group. This rose progressively in successive age groups reaching 79.54% between 4 and 6 years old and a value greater than 90% after 7 years old. From 3 to 17 months even the geometric mean of antibodies to PRP was below the protective limit. Our data indicate that, even in Italy, the majority of the infant population is not protected against H. influenzae, and therefore that vaccination should also be introduced in this country.
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PMID:Immunity to Haemophilus influenzae type b on sample population from central Italy. 150 41

A polyribosylribitol phosphate (polysaccharide)-tetanus protein conjugate vaccine (PRP-T) against Haemophilus influenzae type b (Hib) was evaluated for safety and efficacy after vaccination of more than 100,000 infants. No major side effects were attributed to the vaccine. Immunogenicity studies showed an antibody response in 70% to 100% of infants after two doses, and in 98% to 100% of infants after three doses, within the first 6 months of life. Antibodies persisted in 90% of recipients, in whom significant anamnestic responses developed after a booster dose at 18 months of age. In comparison with other available Hib vaccines, PRP-T induces equal or higher mean titers after three doses. Although licensure of other vaccines interrupted controlled efficacy trials, up to that point five cases of Hib disease in those trials had occurred in placebo recipients, and no Hib disease has been reported in the more than 100,000 vaccinated infants who have received more than one dose of PRP-T. Thus PRP-T combined immunogenicity early in life with induction of immunologic memory.
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PMID:Efficacy and safety of a Haemophilus influenzae type b capsular polysaccharide-tetanus protein conjugate vaccine. 151 8

Nearly one-half of infants immunized with Haemophilus influenzae b capsular polysaccharide (polyribosylribitol phosphate; PRP)-protein conjugate produce low-affinity antibody. To test the hypothesis that antibody affinity is linked to biologic function, sera were obtained before and 1 month after immunization of 18-month-old infants with PRP-diphtheria toxoid conjugate vaccine. Correlation was attempted of anti-PRP affinity, concentrations of anti-PRP, and anti-outer membrane proteins and of immunoglobulin isotype with bactericidal activity. Nine subjects produced anti-PRP of low affinity (K less than 10(4) l/mol), and 11 had higher affinity antibodies (average K, 2.8 x 10(4) l/mol). By multiple regression analysis, antibody affinity was the only variable significantly related to the bactericidal activity of serum after immunization with the conjugate vaccine (r = .71; P = .04). Thus, serum anti-PRP from a substantial proportion of infants appeared functionally deficient in association with low-affinity antibody.
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PMID:Correlation between antibody affinity and serum bactericidal activity in infants. 155 7

The measurement of antibodies to the capsular polysaccharide (PRP) of Haemophilus influenzae type b (Hib) is important because vaccines inducing such antibodies are now available. We developed and evaluated an enzyme-linked immunosorbent assay (ELISA) for detection of these antibodies based on direct coating of the plates with tyraminated PRP. The assay fulfilled the requirements for parallel line assays; it was sensitive, specific, and reproducible with a coefficient of variation between days of 19%. Results from the ELISA were compared with results from radioimmunoassay and a correlation coefficient of 0.93 was found. Results obtained by the two methods were proportional and the relation was independent of the antibody level. The relation between them was also unaffected by the contribution of different antibody isotypes, indicating that these were measured to the same extent by both methods. ELISA employing direct coating of the plates with tyraminated PRP represents a useful alternative for detection of antibodies when studying immunogenicity of Hib vaccines.
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PMID:Relation between enzyme-linked immunosorbent assay and radioimmunoassay for detection of antibodies to the capsular polysaccharide of Haemophilus influenzae type b. 155 88


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