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C von Hunolstein

Publications and source records attributed to C von Hunolstein.

At least 19 recordsLinked to original sources
PubMed2004

Antibody classes & subclasses induced by mucosal immunization of mice with Streptococcus pyogenes M6 protein & oligodeoxynucleotides containing CpG motifs.

BACKGROUND & OBJECTIVES: Type-specific antibodies against M protein are critical for human protection as they enhance phagocytosis and are protective. An ideal vaccine for the protection against Streptococcus pyogenes would warrant mucosal immunity, but mucosally administered M-protein has been shown to be poorly immunogenic in animals. We used a recombinant M type 6 protein to immunize mice in the presence of synthetic oligodeoxynucleotides containing CpG motifs (immunostimulatory sequences: ISS) or cholera toxin (CT) to explore its possible usage in a mucosal vaccine. METHODS: Mice were immunized by intranasal (in) or intradermal (id) administration with four doses at weekly intervals of M6-protein (10 microg/mouse) with or without adjuvant (ISS, 10 microg/mouse or CT, 0,5 microg/mouse). M6 specific antibodies were measured by enzyme linked immunosorbent assay using class and subclass specific monoclonal antibodies. RESULTS: The use of ISS induced an impressive anti M-protein serum IgG response but when id administered was not detectable in the absence of adjuvant. When used in, M-protein in the presence of both ISS and CT induced anti M-protein IgA in the bronchoalveolar lavage, as well as specific IgG in the serum. IgG were able to react with serotype M6 strains of S. pyogenes. The level of antibodies obtained by immunizing mice in with M-protein and CT was higher in comparison to M-protein and ISS. The analysis of anti-M protein specific IgG subclasses showed high levels of IgG1, IgG2a and IgG2b, and low levels of IgG3 when ISS were used as adjuvant. Thus, in the presence of ISS, the ratio IgG2a/IgG1 and (IgG2a+IgG3)/IgG1 >1 indicated a type 1-like response obtained both in mucosally or systemically vaccinated mice. INTERPRETATION & CONCLUSION: Our study offers a reproducible model of anti-M protein vaccination that could be applied to test new antigenic formulations to induce an anti-group A Streptococcus (GAS) vaccination suitable for protection against the different diseases caused by this bacterium.

Animals↗
PubMed2002

Penicillin tolerance amongst non-toxigenic Corynebacterium diphtheriae isolated from cases of pharyngitis.

Twenty-four strains of non-toxigenic Corynebacterium diphtheriae biotype gravis from the throats of patients with pharyngitis/tonsillitis were assayed for susceptibility to penicillin and erythromycin using determination of MIC, MBC and time-kill curves. There were no differences between the MICs of penicillin for susceptible and tolerant strains. All but one strain had penicillin MBCs > or = 2 mg/L. Seventy-one per cent (17/24) of the strains were tolerant to penicillin. In contrast, all strains were susceptible to erythromycin (MIC < or = 0.016 mg/L). These aspects should be considered when choosing the therapy for treating non-toxigenic C. diphtheriae pharyngitis/tonsillitis.

Anti-Bacterial Agents↗
PubMed2001

Reactogenicity and immunogenicity of adult versus paediatric diphtheria and tetanus booster dose at 6 years of age.

We evaluated the reactogenicity and immunogenicity of a booster dose of diphtheria-tetanus vaccine administered at the age of school-entry, comparing a low-dose vaccine (dT) to the standard paediatric dose (DT). Participants were randomly assigned to receive one of the two vaccines; the study was evaluator-blinded. The frequency of side-reactions was similar when comparing the two groups, except when considering local redness and swelling, which were significantly more frequent among the DT group. The post-booster geometric mean titre of diphtheria antibodies in the DT group was twice as high as that in the dT group (14.1 IU/ml versus 7.7 IU/ml; P<0.001). The higher antibody response and the comparable reactogenicity indicate that DT should be used as booster at school-entry, particularly if additional booster doses during adolescence or adulthood are not administered.

Antibodies, Bacterial↗
PubMed2001

The adjuvant effect of synthetic oligodeoxynucleotide containing CpG motif converts the anti-Haemophilus influenzae type b glycoconjugates into efficient anti-polysaccharide and anti-carrier polyvalent vaccines.

Synthetic oligodeoxynucleotides containing CpG immunostimulatory sequences (ISS) have been shown to act as potent adjuvants of type 1 immune responses when co-administered with protein or peptide vaccines. We have recently shown that ISS can increase the anti-polysaccharide (CHO) and anti-tetanus toxoid (TT) or anti-diphtheria (CRM) toxoid antibody levels if used as adjuvant of anti-Haemophilus influenzae type b (Hib) CHO vaccine conjugated with TT or CRM. The analysis of anti-TT and anti-CRM IgG subclasses showed a significant increase in IgG2a, IgG2b and/or IgG3 in the presence of ISS. Anti-TT and anti-CRM antibodies were shown to neutralize the activity of both the tetanus and diphtheria toxin in vivo or in vitro tests respectively. These data show that ISS have the potential to increase host antibody response against both the CHO and the protein component of a conjugated vaccine, and encourage the investigation to identify strategies of vaccination with schedules aimed at the valuation of protein carriers as protective immunogens.

Adjuvants, Immunologic↗
PubMed2001

Severity of group B streptococcal arthritis in selected strains of laboratory mice.

The susceptibilities of C3H/HeN, BALB/c, and C57BL/6N mouse strains to group B streptococci (GBS) infection were evaluated. C3H/HeN mice developed severe polyarthitis; mild lesions and no lesions were observed in BALB/c and C57BL/6N mice, respectively. A correlation between the severity of arthritis, the number of GBS in the joints, and local interleukin-6 and interleukin-1beta production was evident.

Animals↗
PubMed2000

Severity of group B streptococcal arthritis is correlated with beta-hemolysin expression.

Septic arthritis is a clinical manifestation of group B streptococcal (GBS) infection in neonates and adults. To examine the potential role of GBS beta-hemolysin in joint injury, mice were infected with 2 wild-type strains or with nonhemolytic (NH) or hyperhemolytic (HH) variants derived by transposon mutagenesis. Compared with mice infected with the parent strains, mice infected with the NH mutants had decreased mortality and bacterial proliferation. A reduced LD(50) and a higher microbial load were obtained in mice infected with the HH mutants. Greater degrees of joint inflammation and damage were observed in the HH mutant-infected animals than in those infected with the parental strains. NH mutant-infected mice manifested only a mild and transient arthritis. Systemic and local levels of interleukin-6 mirrored the observed differences in virulence and severity of arthritis. These data support a direct correlation of GBS beta-hemolysin expression with mortality and severity of articular lesions.

Animals↗
PubMed2000

European sero-epidemiology network: standardisation of the results of diphtheria antitoxin assays.

A European Sero-Epidemiological Network (ESEN) was established with the aim to co-ordinate and harmonise serological surveillance of immunity to communicable diseases in Europe. In this study the inter-laboratory standardisation of diphtheria toxin antibody measurements is reported. A standard panel of 162 sera was tested by the participating laboratories using an in vitro assay of their choice: VERO cell toxin neutralisation assay (NT), double-antigen delayed time-resolved fluorescence immuno-assay (DA-DELFIA), double-antigen enzyme-linked immunosorbent assay (DAE), toxin binding inhibition test (ToBI) and an indirect enzyme-linked immunosorbent assay (ELISA). The results were standardised using regression against the NT. The variations due to inter-laboratory and inter-assay variation, which would otherwise make it difficult directly to compare the main serum bank results by the different laboratories and the various assays were successfully minimised by the standardisation. The regression equations obtained will be used to transform the respective local results of testing the main serum bank into the reference test unitages. This study also gave the opportunity to compare the various assays within and between laboratories. This demonstrated a very high correlation between DA-DELFIA, DAE, ToBI and the NT. The ELISA showed a good correlation, too, however sera below some 0.1 IU/ml were overestimated.

Animals↗
PubMed2000

Influence of interferon-gamma administration on the severity of experimental group B streptococcal arthritis.

OBJECTIVE: To assess the effect of interferon-gamma (IFNgamma) administration on the evolution of systemic infection and septic arthritis induced by group B streptococci (GBS) in mice. METHODS: CD1 mice were inoculated intravenously with arthritogenic strain 1/82 of type IV GBS. Exogenous murine IFNgamma or anti-IFNgamma monoclonal antibodies were administered intravenously either 2 hours (-2 hours) before or 18 hours after infection with 1 x 10(7) GBS. Mice were monitored daily for survival and for signs of arthritis. In a subsequent set of experiments, mice were killed at selected times for examination of bacterial clearance, joint histopathology, and cytokine production. RESULTS: Mortality in mice treated with IFNgamma at -2 hours was 100%, compared with 20% in those treated at 18 hours and with 40% in controls. As indicated by the arthritis score, mice treated with IFNgamma at -2 hours developed early and more severe arthritis, whereas those treated at 18 hours had milder arthritis compared with infected controls. Less severe joint pathology in the mice treated with IFNgamma at 18 hours correlated with low levels of interleukin-6 (IL-6) and IL-1beta and a low bacterial load in the joints, whereas rapid onset and worsening of articular lesions in those treated at -2 hours corresponded to early and sustained levels of IL-6. CONCLUSION: The findings of this study demonstrate that the effects mediated by IFNgamma on GBS-induced arthritis may be detrimental or beneficial, depending on the time of administration of IFNgamma in relation to infection with the antigen.

Animals↗
PubMed2000

Diphtheria antibody levels in the Italian Population.

Immunity to diphtheria was assessed in serum samples obtained from 3111 healthy Italian males and females aged 0-84 years. Diphtheria antitoxin was tested using a double-antigen, time-resolved fluorescence immunoassay (DA-DELFIA). According to internationally accepted criteria, antitoxin concentrations < 0.01 IU/ml indicate susceptibility to diphtheria, those > or = 0.01-0.09 IU/ml provide basic or inadequate protection, and concentrations > or =0.1 IU/ml are protective. By these criteria, 9.9% (95% CI 8.9 to 11.18) of the participants were susceptible to diphtheria, 30.2% (95% CI, 28.6 to 31.9) had basic protection, and 59.9% (95% CI, 58.1 to 61.6) were protected. The prevalence of unprotected individuals showed an age-related increase, up to the 45-49-year-old age group for females and the 50-54-year-old age group for males (34.9% and 31.3% of individuals, respectively). The prevalence of immunity did not significantly differ in relation to sex in any of the age groups. These results indicate that booster shots should be routinely provided to the adult population in order to maintain a protective level of diphtheria antibodies.

Adolescent↗
PubMed2000

Synthetic oligodeoxynucleotide containing CpG motif induces an anti-polysaccharide type 1-like immune response after immunization of mice with Haemophilus influenzae type b conjugate vaccine.

Synthetic oligodeoxynucleotides containing CpG motifs [immunostimulatory sequences (ISS)] have been described as potent adjuvants of type 1 immune responses when co-administered with protein or peptide vaccines. To investigate their role in the immune response to polysaccharides (CHO), different preparations of anti-Haemophilus influenzae type b (Hib) conjugate vaccine were administered to mice. The unconjugated CHO did not induce the synthesis of specific antibodies even in the presence of ISS. On the other hand, anti-CHO-specific antibodies significantly increased in the presence of ISS, when tetanus (TT) or diphtheria [cross-reacting material (CRM)] toxoid-conjugated CHO were used to immunize mice. The adjuvant effect was also observed for the immune response against the carrier protein (TT and CRM). ISS insured an early and long-lasting specific IgG production. The effects of ISS on the anti-CHO immune response could be attributed to the amplification of the T help provided by the carrier. The analysis of anti-CHO IgG subclasses showed a significant increase of IgG2a and IgG3 in the presence of ISS. ISS caused a rapid release of IL-12 and IFN-gamma in sera from treated mice. This data provide a first evidence for the ability of ISS to induce an anti-CHO type 1-like immune response and demonstrate that ISS have the potential to increase host antibody response against both the CHO and the protein component of a conjugated vaccine.

Adjuvants, Immunologic↗
PubMed2000

Human monocyte receptors involved in tumor necrosis factor responses to group B streptococcal products.

Several group B streptococcal products have been previously found to stimulate human monocytes to produce tumor necrosis factor alpha. In order to identify the receptors involved in these responses, monocytes were stimulated with purified group- or type-specific carbohydrates or lipoteichoic acid in the presence of anti-receptor monoclonal antibodies, soluble CD14, or lipopolysaccharide-binding protein. Results indicate that CD14 plays an important role in tumor necrosis factor alpha responses to all of the stimuli tested. Moreover, both CD14 and complement receptor type 3 may be involved in responses to the group-antigen.

Animals↗
PubMed1999

Determination of the molecular size distribution of Haemophilus influenzae type b-tetanus toxoid conjugate vaccines by size-exclusion chromatography.

The molecular size of Haemophilus influenzae (Hib) type b polysaccharide-protein conjugate vaccines is an important physico-chemical parameter which correlates with immunogenicity. This paper describes the experimental conditions for high-performance size-exclusion chromatography on a PL Aquagel-OH 60 column to determine the size distribution of Hib high-molecular-weight conjugate vaccines.

Bacterial Vaccines↗
PubMed1999

A routine high-performance size-exclusion chromatography to determine molecular size distribution of Haemophilus influenzae type b conjugate vaccines.

High-performance size exclusion chromatography has been used to determine the molecular size distribution of Haemophilus influenzae type b (Hib) conjugate vaccines. Both high molecular weight preparations of native Hib capsular polysaccharide coupled to tetanus toxoid and low molecular weight vaccines with Hib oligosaccharides linked to the CRM197 nontoxic mutant diphtheria protein were analysed. Columns with different fractionation ranges were used for the two kinds of vaccines. This method showed to be rapid, accurate and reproducible for different lots of Hib vaccine of different composition produced by various manufacturers. It could replace more time-consuming chromatographic methods enabling control authorities to employ a single methodological approach for different Hib vaccines.

Bacterial Proteins↗
PubMed1999

Role of tumor necrosis factor alpha, interleukin-1beta, and interleukin-6 in a mouse model of group B streptococcal arthritis.

Intravenous inoculation of CD1 mice with 10(7) CFU of type IV group B Streptococcus (GBS IV) results in a high incidence of diffuse septic arthritis. In this study the roles of tumor necrosis factor alpha (TNF-alpha), interleukin-1beta (IL-1beta), and IL-6 in articular pathology were evaluated. Cytokine levels were quantified in the serum and joints by enzyme-linked immunosorbent assay in mice injected with GBS IV and tested or not tested with pentoxifylline (PTF), a methylxanthine that affects cytokine production. PTF was administered intraperitoneally at a dose of 1 mg/mouse (50 mg/kg of body weight) 1 h after GBS infection and then at 24-h intervals for 4 days. High levels of IL-1beta and IL-6, but not TNF-alpha, were detected in the joints of mice injected with GBS IV from 5 to 15 days after infection, when articular lesions were most frequent and severe. IL-1beta and IL-6 concentrations in the joints significantly (P < 0.001) exceeded those detected in the serum, confirming a strong local production. PTF treatment resulted in a strong reduction of cytokine production and in a marked decrease in both the incidence and severity of arthritis. Inoculation of exogenous murine recombinant IL-1beta or IL-6 in mice treated with GBS IV plus PTF resulted in an incidence and severity of articular lesions similar to those obtained with inoculation of GBS IV alone. No significant effect was obtained with TNF-alpha administration. These data show a strong involvement of IL-1beta and IL-6, but not TNF-alpha, in the pathogenesis of GBS arthritis.

Animals↗
PubMed1998

Group B streptococci persist inside macrophages.

Group B streptococci (GBS) are an important cause of neonatal sepsis, pneumonia and meningitis. In the early phase of infection, macrophages and polymorphonuclear cells (PMN) are the first immune cells that interact with GBS. In this in vitro study, to gain insight into GBS-macrophage interaction in the absence of type-specific antibodies, we examined the features of GBS survival in thioglycollate-elicited murine peritoneal macrophages and the effect of GBS on the protein kinase C (PKC)-dependent transduction pathway. Our results demonstrate that type Ia GBS, strain 090 (GBS-Ia) and type III GBS strain COH 31r/s (GBS-III), after in vitro phagocytosis survive and persist intracellularly in macrophages for up to 24 and 48 hr, respectively. However, macrophage activation by interferon-gamma (IFN-gamma) and lipopolysaccharide from Escherichia coli (LPS) caused a significant reduction in the time of intracellular persistence. Macrophage activation by IFN-gamma and LPS seems to be a multifactorial event involving multiple intracellular signal pathways also including PKC. Since PKC is one of the components in the signal network leading to macrophage activation and an important target for several intracellular micro-organisms, we wondered whether PKC could have a role in intracellular GBS survival. Both PKC depletion by treatment with phorbol 12-myristate 13-acetate (PMA) for 18 hr and PKC inhibition by Calphostin C rendered macrophages more permissive for the intracellular GBS survival. Furthermore, GBS-infected macrophages were unable to respond to PMA and LPS, activators of PKC, by inducing antimicrobial activity. The ability of GBS to impair PKC-dependent cell signalling was also demonstrated by the reduced c-fos gene expression in GBS-infected macrophages with respect to control macrophages, after LPS stimulation. In conclusion, our results indicate that GBS survive in macrophages and impairment of PKC signal transduction contributes to their intracellular survival.

Animals↗
PubMed1998

Role of group B streptococcal capsular polysaccharides in the induction of septic arthritis.

The ability of different serotypes of group B streptococci (GBS) to induce septic arthritis in mice was compared. Types II, III, IV, V, VI and VII GBS were investigated. A highly capsulate strain of type III GBS, COH1, and its mutants, COH1-11 (lacking capsular sialic acid) and COH1-13 (non-capsulate), obtained by transposon insertional mutagenesis, were used to assess the role of type-specific polysaccharide on the induction of arthritis. At an intravenous dose of 10(7) cfu/mouse, reference strains of types II, III, IV, VI and VII and type III strain COH1 induced arthritis with an incidence ranging from 70 to 90%. For type V and strain COH1-11, 10(8) cfu/mouse was required to obtain a 50% incidence of arthritis; lesions were not evident with strain COH1-13. The presence of the capsule played a major role in the induction of GBS septic arthritis. The presence and amount of sialic acid in capsular polysaccharide influenced the incidence of articular lesions. The bacterial dose affected the manifestations of arthritis; the less virulent strains of GBS also induced articular lesions when an adequate number of micro-organisms reached the joints.

Animals↗