Serum IgG Antibody Levels Research Articles

Structure and biological activity of protopanaxatriol-type saponins from the roots of Panax notoginseng

The further purification of the total saponins from the roots of Panax notoginseng by using ordinary and reversed-phase silica-gel, as well as Sephadex LH-20 chromatography afford seven adjuvant active protopanaxatriol-type saponins (PTS), ginsenosides-Rh 1 (Rh 1),-Rh 4 (Rh 4),-Rg 1 (Rg 1),-Re (Re), notoginsenosides-R 1 (R 1),-R 2 (R 2),-U (U). These saponins were evaluated for their haemolytic activities and adjuvant potentials on the cellular and humoral immune responses of ICR mice against ovalbumin (OVA). The effect of the substitution pattern of these PTS on their biological activities was investigated and structure-activity relationships were established. Among seven PTS, the haemolytic activity of Rh 1 was higher than that of other six compounds ( p < 0.001) The HD 50 values of Rh 4 and U were significantly bigger than those of R 2, Rg 1 and Re ( p < 0.05 or p < 0.01). Seven PTS could significantly increase the concanavalin A (Con A)-, lipopolysaccharide (LPS)- and OVA-induced splenocyte proliferation in the OVA-immunized mice ( p < 0.01 or p < 0.001). The OVA-specific IgG, IgG1, IgG2a and IgG2b antibody levels in serum were also significantly enhanced by seven PTS compared with OVA control group ( p < 0.01 or p < 0.001). The structure-activity relationship studies suggested that the number, the length and the position of sugar side chains, and the type of glucosyl group in the structure of PTS could not only affect their haemolytic activities and adjuvant potentials, but have significant effects on the nature of the immune responses. The information about this structure/function relationship might be useful for developing semisynthetic tetracyclic triterpenoid saponin derivatives with immunological adjuvant activity, as well as a reference to the distribution of the functional groups composing the saponin molecule.

Periodontal Disease and Coronary Heart Disease

Results from studies relating periodontal disease to cardiovascular disease have been mixed. Residual confounding by smoking and use of clinical measures of periodontal disease rather than measures of infection have been 2 major criticisms. The aims of this study were to investigate relationships between prevalent coronary heart disease (CHD) and 2 exposures, (1) clinical periodontal disease and (2) IgG antibodies to 17 oral organisms, and to evaluate the role of smoking in these relationships. Our study is based on a subset of participants in the Atherosclerosis Risk in Communities (ARIC) Study, who received a complete periodontal examination during visit 4 (1996-1998). The exposures were periodontal status and serum IgG antibody levels against 17 periodontal organisms, and the outcome was prevalent CHD at visit 4. Multivariable analyses indicate that periodontal status is not significantly associated with CHD in either ever smokers or never smokers. Similar analyses evaluating antibodies indicate that high antibodies (above the median) to Treponema denticola (odds ratio [OR]=1.7; 95% CI, 1.2 to 2.3), Prevotella intermedia (OR=1.5; 95% CI, 1.1 to 2.0), Capnocytophaga ochracea (OR=1.5; 95% CI, 1.1 to 2.1), and Veillonella parvula (OR=1.7; 95% CI, 1.2 to 2.3) are significantly associated with CHD among ever smokers, whereas Prevotella nigrescens (OR=1.7; 95% CI, 1.1 to 2.6), Actinobacillus actinomycetemcomitans (OR=1.7; 95% CI, 1.2 to 2.7), and Capnocytophaga ochracea (OR=2.0; 95% CI, 1.3 to 3.0) were associated with CHD among never smokers. Clinical signs of periodontal disease were not associated with CHD, whereas systemic antibody response was associated with CHD in ever smokers and never smokers. These findings indicate that the quality and quantity of the host response to oral bacteria may be an exposure more relevant to systemic atherothrombotic coronary events than clinical measures.

Temporal Relationship Between Elevation of Epstein-Barr Virus Antibody Titers and Initial Onset of Neurological Symptoms in Multiple Sclerosis

Infection with Epstein-Barr virus (EBV) has been associated with an increased risk of multiple sclerosis (MS), but the temporal relationship remains unclear. To determine whether antibodies to EBV are elevated before the onset of MS. Nested case-control study conducted among more than 3 million US military personnel with blood samples collected between 1988 and 2000 and stored in the Department of Defense Serum Repository. Cases were identified as individuals granted temporary or permanent disability because of MS. For each case (n = 83), 2 controls matched by age, sex, race/ethnicity, and dates of blood sample collection were selected. Serial samples collected before the onset of symptoms were available for 69 matched case-control sets. Antibodies including IgA against EBV viral capsid antigen (VCA), and IgG against VCA, nuclear antigens (EBNA complex, EBNA-1, and EBNA-2), diffuse and restricted early antigens, and cytomegalovirus. The average time between blood collection and MS onset was 4 years (range, <1-11 years). The strongest predictors of MS were serum levels of IgG antibodies to EBNA complex or EBNA-1. Among individuals who developed MS, serum antibody titers to EBNA complex were similar to those of controls before the age of 20 years (geometric mean titers: cases = 245, controls = 265), but 2- to 3-fold higher at age 25 years and older (cases = 684, controls = 282; P<.001). The risk of MS increased with these antibody titers; the relative risk (RR) in persons with EBNA complex titers of at least 1280 compared with those with titers less than 80 was 9.4 (95% confidence interval [CI], 2.5-35.4; P for trend <.001). In longitudinal analyses, a 4-fold increase in anti-EBNA complex or anti-EBNA-1 titers during the follow-up was associated with a 3-fold increase in MS risk (EBNA complex: RR , 3.0; 95% CI, 1.3-6.5; EBNA-1: RR, 3.0; 95% CI, 1.2-7.3). No association was found between cytomegalovirus antibodies and MS. These results suggest an age-dependent relationship between EBV infection and development of MS.

Association of HLA-DRB3*0202 and serum IgG antibodies to Chlamydia pneumoniae with essential hypertension in a highly homogeneous population from Majorca (Balearic Islands, Spain)

Separate studies investigating the relationship of essential hypertension (EH) with the HLA system and with Chlamydia pneumoniae (C. pneumoniae) infection have given conflicting results. Our aim was to clarify these relationships and determine whether the HLA system and C. pneumoniae infection interact with respect to the risk for EH. An association study (110 essential hypertensives and 107 controls) was conducted in a highly homogeneous population in the Balearic Island of Majorca (Spain). Molecular typing of HLA-B and HLA-DRB and quantification of serum levels of IgG antibodies to C. pneumoniae (sIgGa-Cp) were determined. Student's t-test, chi(2)-statistics, logistic regression analysis, and general linear model ANOVA were used for statistical analysis. The results showed that EH was related with HLA-DRB3*0202 in the whole study population, and with levels of sIgGa-Cp>63.5 BU/ml in the group of individuals with sIgGa-Cp>30 BU/ml (OR (95% CI) adjusted for obesity, familial history of EH and diabetes=2.06 (1.07-3.97), P=0.03, and =4.60 (1.06-19.90), P=0.04, respectively). The association between EH and sIgGa-Cp was observed in the DRB3*0202(+) individuals, but not in the DRB3*0202(-) subgroup (OR (95% CI)=11.14 (1.92-64.54), P=0.004, and =0.98 (0.22-4.43), P=0.64, respectively (P of the Mantel-Haenszel test for homogeneity of OR=0.06)). In our population, EH was positively associated with HLA-DRB3*0202 and with high levels of sIgGa-Cp. Moreover, a significant interaction of DRB3*0202 on the effect of sIgGa-Cp was observed, as the association of EH with these antibodies depended on the presence of DRB*0202.

Associations between IgG antibody to oral organisms and carotid intima–medial thickness in community-dwelling adults

Aims The aims of this study are to describe the relationships between IgG antibodies to 17 oral organisms and atherosclerosis as indexed by carotid intima–medial wall thickness (IMT) and to evaluate the role of smoking. Methods and results Our study is based on a subset of participants in the Atherosclerosis Risk in Communities (ARIC) Study, who received a complete periodontal examination during visit 4 (1996–1998). The outcome was mean carotid IMT ≥ 1 mm assessed by B-mode ultrasound. The exposures were serum IgG antibody levels against 17 periodontal organisms using a whole bacterial checkerboard immunoblotting technique. Evaluation of all 17 antibodies indicated that antibody to Campylobacter rectus resulted in the best-fitting model (OR = 2.3, 95% CI = 1.83–2.84) and individuals with both high C. rectus and Peptostreptococcus micros titers had almost twice the prevalence of IMT ≥ 1 mm than those with only a high C. rectus antibody (8.3% versus 16.3%). Stratification by smoking indicated that all microbial models significant for smokers were also significant for never smokers except for Porphyromonas gingivalis ( p = 0.08). Conclusions This is the first study to report a relationship between IgG antibody reactive to oral organisms and subclinical atherosclerosis with significant relationships evident in both ever and never smokers.

Adjuvant effect of ethanol extract of Semen Cuscutae on the immune responses to ovalbumin in mice

An ethanol extract of Semen Cuscutae (EESC) was evaluated for its adjuvant potentials on the cellular and humoral immune responses of ICR mice against ovalbumin (OVA). ICR mice were immunized subcutaneously with OVA 100 μg alone or with OVA 100 μg dissolved in saline containing aluminum hydroxide gel (Alum) (200 μg), Quil A (10 or 50 μg) or EESC (100, 200 or 400 μg) on Days 1 and 15. Two weeks later (Day 28), concanavalin A (Con A)-, pokeweed (PWM)- and OVA-stimulated splenocyte proliferation and OVA-specific antibody in serum were investigated. EESC significantly enhanced the Con A-, PWM-, and OVA-induced splenocyte proliferation in OVA-immunized mice at a dose of 200 μg ( P < 0.05 or P < 0.025). OVA-specific IgG, IgG1 and IgG2b antibody levels in serum were significantly enhanced by EESC compared with OVA control group ( P < 0.025). Moreover, enhancing effects of EESC on these OVA-specific antibody responses to OVA in mice were more significant than those of Alum and Quil A ( P < 0.025). In conclusion, the results suggest that EESC is effective on Th1 and Th2 cell functions, and could be safely used as adjuvant.

Clostridium difficile toxoid vaccine in recurrent C. difficile-associated diarrhea

Recurrent C difficile -associated diarrhea (CDAD) is associated with a lack of protective immunity to C difficile toxins. A parenteral C difficile vaccine containing toxoid A and toxoid B was reported previously to be safe and immunogenic in healthy volunteers. Our aim was to examine whether the vaccine is also well tolerated and immunogenic in patients with recurrent CDAD. Subjects received 4, 50-microg intramuscular inoculations of the C difficile vaccine over an 8-week period. Serum antitoxin antibodies were measured by ELISA, and toxin neutralizing activity was evaluated using the tissue culture cytotoxin assay. Three patients with multiple episodes of recurrent CDAD were vaccinated. Two of the 3 showed an increase in serum IgG antitoxin A antibodies (3-fold and 4-fold increases, respectively) and in serum IgG antitoxin B antibodies (52-fold and 20-fold, respectively). Both also developed cytotoxin neutralizing activity against toxin A and toxin B. Prior to vaccination, the subjects had required nearly continuous treatment with oral vancomycin for 7, 9, and 22 months, respectively, to treat recurrent episodes of CDAD. After vaccination, all 3 subjects discontinued treatment with oral vancomycin without any further recurrence. A C difficile toxoid vaccine induced immune responses to toxins A and B in patients with CDAD and was associated with resolution of recurrent diarrhea. The results of this study support the feasibility of active vaccination against C difficile and its toxins in high-risk individuals but must be validated in larger, randomized, controlled trials.

Disparate MHC class II haplotypes in myelin oligodendrocyte glycoprotein- and myelin basic protein-induced experimental autoimmune encephalomyelitis

The major histocompatibility complex (MHC) regulates multiple sclerosis (MS) and its model experimental autoimmune encephalomyelitis (EAE). We created four new intra-MHC recombinant rat strains, between the MHC haplotypes RT1 n (BN) and RT1 l (LEW) on the LEW background, to define disease regulation and localization within the MHC. Immunization with recombinant myelin oligodendrocyte glycoprotein (a.a.1-125; MOG)/IFA induced EAE in strains expressing the MHC class II allele RT1.B n, whereas strains expressing the RT1.B l were resistant. In myelin basic protein peptide (MBP GP63-88)/CFA-induced EAE, RT1.B l expressing strains were susceptible whereas strains expressing the RT1.B n were resistant. High levels of antigen-specific IFN-γ secreting lymphoid cells and antigen-specific serum IgG antibodies were only recorded in rats with an MHC class II allele that permitted MOG- or MBP-EAE, respectively. Genetically, we localized the MHC regulation of the investigated EAE models to the central part of the MHC, containing the MHC class II (RT1.B/D) and the centromeric parts of the MHC class III. No influences were evident from the classical MHC class I (RT1.A), the telomeric parts of the MHC class III or the non-classical MHC class I (RT1.C/E/M) in contrast to previous reports. The MHC class II haplotype-specific regulation of EAE induced with two different CNS antigens demonstrates a strikingly specific MHC-association even within the same target organ.

Antibodies to N-homocysteinylated albumin as a marker for earlyonset coronary artery disease in men

N-homocysteinylated (Nepsilon-Hcy) proteins and corresponding antibodies have recently been discovered in humans and animals. Increased autoimmune response to Nepsilon-Hcy-proteins has been reported in stroke patients. The aim of the present study was to investigate whether antibodies against N-homocysteinylated albumin are associated with coronary artery disease (CAD). We studied 88 male patients aged 50 years or under with angiographically documented CAD and 100 age-matched apparently healthy men as controls. Serum levels of IgG antibodies against Nepsilon-Hcy-albumin were determined using an enzymelinked immunosorbent assay. Seropositivity to anti-Nepsilon-Hcy-albumin antibodies was 5-fold more frequent in CAD patients than in controls (52.3% vs 10.0%; p<0.0001). Plasma Hcy levels in CAD patients were also significantly higher in the former than in the latter group (medians, 13.0 microM vs 12.1 microM; p=0.026). Importantly, 41.2% of subjects with plasma total Hcy >14.5 mM were seropositive compared with 25.5% of normohomocysteinemic individuals (p=0.048). There was a weak correlation between anti-Nepsilon-Hcy-albumin antibodies and Hcy levels (r=0.16; p=0.03). By multivariate logistic regression analysis, seropositivity to anti-Nepsilon-Hcy-albumin antibodies was an independent predictor of early CAD (OR, 14.82; 95% CI, 4.47 to 49.19; p=0.00002). Interestingly, anti-Nepsilon-Hcy-albumin antibodies were associated with C-reactive protein levels (r=0.24; p=0.002). Seropositivity to anti-Nepsilon-Hcy-albumin antibodies showed no association with the MTHFR C677T polymorphism. Our results suggest that seropositivity to antibodies against Nepsilon-homocysteinylated albumin is associated with early-onset CAD. An autoimmune response to Nepsilon-Hcy-albumin may represent a novel mechanism involved in the early development of CAD.

Haemolytic activities and adjuvant effect ofGynostemma pentaphyllum saponins on the immune responses to ovalbumin in mice

In this study, the haemolytic activities of Gynostemma pentaphyllum saponins (GPS) and its adjuvant potential on the immune responses of ICR mice against ovalbumin (OVA) were evaluated. GPS showed a slight haemolytic effect, with its haemolytic activity being 10.20% and 4.90% at concentrations of 500 and 250 microg/mL, respectively. ICR mice were immunized subcutaneously with OVA 100 microg alone or with OVA 100 microg dissolved in saline containing aluminium hydroxide gel (Alum, 200 microg), QuilA (10 and 20 microg) or GPS (50, 100 or 200 microg) on days 1 and 15. Two weeks later (day 28), concanavalin A (Con A)-, lipopolysaccharide (LPS)- and OVA-stimulated splenocyte proliferation and OVA-specific antibodies in serum were measured. GPS significantly enhanced the Con A-, LPS- and OVA-induced splenocyte proliferation in the OVA-immunized mice, especially at a dose of 100 microg (p < 0.05 or p < 0.001). OVA-specific IgG, IgG1 and IgG2b antibody levels in serum were also significantly enhanced by GPS compared with the OVA control group (p < 0.05, p < 0.01 or p < 0.001). In conclusion, the results suggest that GPS could be used safely as an adjuvant with low or no haemolytic effect.

Future Vaccine Development at NICHD

Using published data and the results of our studies, we hypothesized that a critical level of serum IgG antibodies to the surface structures of invasive pathogens (capsular polysaccharides of Haemophilus influenzae type b, pneumococcus, meningococcus, Salmonella typhi, Escherichia coli, and Staphylococcus aureus, the O-specific polysaccharide LPS domain of the LPS of Shigella, non-typhoidal Salmonella, and E. coli, and the capsular polypeptide of Bacillus anthraces) confer immunity to these pathogens. Covalent attachment to a protein increases their immunogenicity and bestows T-cell properties to these antigens. We have also shown that a critical level of serum IgG antibodies to pertussis toxin alone induces immunity on both an individual and on a community basis (herd immunity) to Bordetella pertussis. It is likely that all the above conjugates and pertussis toxoid will be incorporated into vaccines for routine infant immunization.

Chronic rhinosinusitis: An enhanced immune response to ubiquitous airborne fungi

Chronic rhinosinusitis (CRS) is one of the most common long-term illnesses in the United States. The etiology of CRS is unknown, and no effective treatment has been established. We investigated the hypothesis that abnormal immunologic responses to ubiquitous airborne fungi contribute to the pathogenesis of this disease. The proliferative and cytokine responses of PBMCs to extracts from 4 common airborne fungi-including Alternaria , Aspergillus , Cladosporium , and Penicillium -were examined by in vitro culture. Serum specimens were tested for specific IgE and IgG to these fungi. PBMCs from approximately 90% of the patients with CRS, but not those from normal individuals, produced both IL-5 and IL-13 when exposed to Alternaria. Furthermore, PBMCs from patients with CRS produced significantly more IFN-gamma than PBMCs from normal individuals in response to Alternaria (median, 553 pg/mL vs 98 pg/mL; P < .01). Levels of serum IgG antibodies to Alternaria and Cladosporium were clearly increased in patients with CRS compared with normal individuals ( P < .01). Less than 30% of the patients with CRS had specific IgE antibodies to Alternaria or Cladosporium. The increased humoral (serum IgG) response strongly correlated with the increased cellular (IL-5 production) response to Alternaria ( r = 0.619; P < .01). Patients with CRS show exaggerated humoral and cellular responses, both T(H)1 and T(H)2 types, to common airborne fungi, particularly Alternaria. The anomalous immune and inflammatory responses to ubiquitous fungi may explain the chronicity of airway inflammation in CRS.

Hepatocyte Growth Factor Ameliorates Chronic Graft-Versus-Host Disease.

Since chronic graft-versus-host disease (GVHD) is a major cause of morbidity and mortality in allogeneic hematopoietic stem cell transplantation (HSCT), a new strategy to prevent chronic GVHD is necessary. We previously showed that hepatocyte growth factor (HGF) protected against lethal effects of acute GVHD and promoted T cell reconstitution in murine models (J Clin Invest 107;1365: 2001, Blood 2004 in press). We have now investigated whether HGF can protect against chronic GVHD. (C57BL/6 x DBA/2) F1 (BDF1) recipient mice were lethally irradiated (9 Gy) and co-transplanted with 5 x 106 bone marrow cells and 1.5 x 107 spleen cells from C57BL/6 donor mice. At the same time, mice were injected intramuscularly with 8 microgram of the human HGF gene, or with a control mock vector, every week using liposomes containing the hemagglutinating virus of Japan. Untreated GVHD recipients showed significant atrophy of the spleen and the thymus on day 56 after transplantation, while HGF treatment effectively prevented this atrophy. Splenic T cells from untreated GVHD recipients proliferated and produced significant amounts of IL-4 after being exposed to irradiated BDF1 spleen cells in vitro, while those from HGF-treated GVHD recipients did not. These results suggest that host-reactive type 2 T helper (Th2) cells were eliminated in the HGF-treated GVHD recipients by protection against thymic damage caused by acute GVHD, thereby preventing the progression to chronic GVHD. We next used DBA/2 into BDF1 models to determine the effect of HGF on another type of chronic GVHD. Chronic GVHD was induced by injection of DBA/2 spleen cells (9 x 107) into non-irradiated BDF1 mice. HGF treatment effectively prevented proteinuria and histological changes associated with glomerulonephritis. Liver sections of untreated GVHD recipients revealed prominent primary biliary cirrhosis (PBC)-like changes, as indicated by lymphocyte infiltration into the periportal area of the liver. HGF treatment effectively prevented these histological changes. HGF treatment greatly reduced the number of splenic B cells and the serum IgG and anti-DNA antibody levels. Furthermore, HGF treated GVHD recipients showed down-regulation of IL-4 mRNA expression in the spleen, liver and kidneys. IL-4 induction from DBA/2 CD4+ T cells stimulated by irradiated BDF1 CD11c+ dendritic cells (DCs) was significantly inhibited by addition of recombinant HGF (10 ng/ml) in vitro. Taken together, these results indicate that HGF can prevent chronic GVHD by eliminating host-reactive Th2 cells in the thymus, or by inhibition of Th2 cell induction by interaction with DCs.

Foal IgG and opsonizing anti- Rhodococcus equi antibodies after immunization of pregnant mares with a protective VapA candidate vaccine

The aim of this study was to evaluate serum IgG antibody levels and opsonizing activity in foals from pregnant mares immunized with either proteins from an R. equi strain containing virulence-associated protein A (VapA), an immunodominant surface-expressed lipoprotein encoded by a virulence plasmid crucial for virulence in foals, or a whole killed virulent R. equi preparation. Forty-eight pregnant mares were distributed into three groups, i.e. 24 immunized with R. equi VapA protein antigen associated with a water-based nanoparticle adjuvant (Montanide IMS 3012), 8 immunized with whole killed R. equi, and 16 non-immunized as control. Serum IgG and opsonizing capacity were evaluated during pregnancy in mares, and up to day 45 post-delivery in foals in which R. equi infections were recorded in the first 6 months of life. Pregnant mares immunized with virulent R. equi proteins developed higher serum IgG and opsonic activity which were transferred to the foals than either in the whole R. equi immunized or the control group. Four foals developed pneumonia in the control group while none in immunized groups. Results support further evaluation of VapA protein antigen associated with a water-based nanoparticle adjuvant as a candidate vaccine for immunization of pregnant mares resulting in passive antibody-mediated protection of foals.

Antibodies to periodontal pathogens and stroke risk.

The association between cerebrovascular events and periodontitis has been found in few studies based on clinical periodontal examinations. However, evidence on the association between periodontal pathogens and stroke is lacking. Therefore, the aim of the study was to investigate whether elevated levels of serum antibodies to major periodontal pathogens predict stroke in a case-control study. The study population comprised 6950 subjects (aged 45 to 64 years) who participated in the Mobile Clinic Health Survey in 1973 to 1976 in Finland. During a follow-up of 13 years, a total of 173 subjects had a stroke. From these, 64 subjects had already experienced a stroke or had signs of coronary heart disease (CHD) at baseline, whereas 109 subjects were apparently healthy. Two controls per case were matched for age, gender, municipality, and disease status. Serum IgG and IgA class antibody levels to the periodontal pathogens, Actinobacillus actinomycetemcomitans and Porphyromonas gingivalis, were determined by multiserotype enzyme-linked immunosorbent assay. The cases identified during the follow-up that were free of stroke or CHD at baseline were more often IgA-seropositive for A. actinomycetemcomitans than were their controls, 41.3% versus 29.3%. Compared with the seronegative, the seropositive subjects had a multivariate odds ratio of 1.6 (95% CI, 1.0 to 2.6) for stroke. The patients with a history of stroke or CHD at baseline were more often IgA-seropositive for P. gingivalis than were their controls, 79.7% versus 70.2%. When compared with the seronegative, the seropositive subjects had an odds ratio of 2.6 (1.0 to 7.0) for secondary stroke. The present prospective study provides serological evidence that an infection caused by major periodontal pathogens is associated with future stroke.

Gene expression signatures in chronic and aggressive periodontitis: a pilot study.

This pilot study examined gene expression signatures in pathological gingival tissues of subjects with chronic or aggressive periodontitis, and explored whether new subclasses of periodontitis can be identified based on gene expression profiles. A total of 14 patients, seven with chronic and seven with aggressive periodontitis, were examined with respect to clinical periodontal status, composition of subgingival bacterial plaque assessed by checkerboard hybridizations, and levels of serum IgG antibodies to periodontal bacteria assayed by checkerboard immunoblotting. In addition, at least two pathological pockets/patient were biopsied, processed for RNA extraction, amplification and labeling, and used to study gene expression using Affymetrix U-133 A arrays. Based on a total of 35 microarrays, no significantly different gene expression profiles appeared to emerge between chronic and aggressive periodontitis. However, a de novo grouping of the 14 subjects into two fairly robust clusters was possible based on similarities in gene expression. These two groups had similar clinical periodontal status and subgingival bacterial profiles, but differed significantly with respect to serum IgG levels against the important periodontal pathogens Porphyromonas gingivalis, Tannerella forsythensis and Campylobacter rectus. These early data point to the usefulness of gene expression profiling techniques in the identification of subclasses of periodontitis with common pathobiology.

Adjuvant effect of Panax notoginseng saponins on the immune responses to ovalbumin in mice

In this study, the haemolytic activities of Panax notoginseng saponins (PNS) and its adjuvant potentials on the cellular and humoral immune responses of ICR mice against ovalbumin (OVA) were evaluated. We determined the haemolytic activity of PNS using 0.5% rabbit red blood cell. PNS showed a slight haemolytic effect, with its haemolytic percents being 11.59 and 3.60% at the concentrations of 500 and 250 μg/ml, respectively. Furthermore, the adjuvant potential of PNS at three dose levels on the cellular and humoral immune responses of ICR mice against ovalbumin were investigated. ICR mice were immunized subcutaneously with OVA 100 μg alone or with OVA 100 μg dissolved in saline containing aluminum hydroxide gel (Alum) (200 μg), Quil A (10 and 50 μg) or PNS (50, 100 or 200 μg) on days 1 and 15. Two weeks later (day 28), concanavalin A (Con A)-, pokeweed (PWM)- and OVA-stimulated splenocyte proliferation and OVA-specific antibodies in serum were measured. PNS significantly enhanced the Con A-, PWM-, and OVA-induced splenocyte proliferation in the OVA-immunized mice at a dose of 100 μg ( P < 0.05 or P < 0.025). OVA-specific IgG, IgG1 and IgG2b antibody levels in serum were significantly enhanced by PNS compared with OVA control group ( P < 0.025). Moreover, enhancing effect of PNS on the OVA-specific IgG2b antibody responses to OVA in mice were more significant than that of Quil A ( P < 0.025). In conclusion, the results suggest that PNS could be safely used as adjuvant with low or non-haemolytic effect.

Human antibody response to surface layer proteins in Clostridium difficile infection

Clostridium difficile is a major cause of infectious diarrhoea in hospitalised patients. Surface layer proteins (SLPs) are the most abundant surface localised proteins expressed by C. difficile. The aim of this study was to examine the humoral immune response to C. difficile SLPs and its potential role in protection from C. difficile associated diarrhoea (CDAD). Serum antibodies to SLPs from C. difficile were measured by ELISA in a cohort of 146 patients (55 patients with CDAD, 34 asymptomatic carriers, and 57 controls). No significant difference was detected in serum IgM, IgA or IgG antibody levels between cases, carriers or control groups at any of the time points tested. However, patients with recurrent episodes of C. difficile diarrhoea had significantly lower IgM-anti-SLP levels than patients with a single episode on days 1, 3, 6 and 9 ( p=0.05, p=0.009, p=0.02, p=0.049). The adjusted odds ratio for recurrent diarrhoea associated with a low day 3 serum IgM anti-SLP antibody level was 24.5 (95% confidence interval; 1.6–376.3). Further studies which examine the specific anti-SLP antibody responses to the colonising strain are warranted to determine if immune responses to C. difficile SLPs play a role in protection from CDAD.

Amelioration of murine antigen-induced arthritis by dehydroepiandrosterone (DHEA)

Sex hormones have immunomodulatory properties and may play an important role in the pathogenesis of autoimmune diseases like rheumatoid arthritis (RA). This study sought to examine the effects of the natural weak androgen dehydroepiandrosterone (DHEA) and its metabolite androstenediol (AED) on the development of murine antigen-induced arthritis (AIA). DHEA and AED were administered orally, approximately 10 mg/day, from the time of AIA induction (i.e., 3 weeks after start of immunization) in young male as well as young and old female C57BL/6 mice. The effects were assessed in terms of joint swelling, histological changes, and cell-mediated and humoral immunity. Compared to untreated AIA animals, continuous administration of DHEA decreased knee joint swelling during acute and chronic AIA, as well as histological signs of inflammation and joint destruction during chronic AIA. These effects were age- and gender-independent. Delayed-type hypersensitivity (DTH) to the specific antigen methylated bovine serum albumin (mBSA) was significantly reduced, but there were no changes in the balance of the T helper (Th) cell subsets Th1/Th2, as tested by the ratio of IgG isotypes in the sera. Whereas serum levels of IgG antibodies to mBSA were not influenced, the formation of IgG autoantibodies to the matrix constituents collagen type I, collagen type II, and cartilage proteoglycans was significantly inhibited. In all experiments, the effects of AED were not significantly stronger than those of DHEA. Administration of exogenous DHEA ameliorates the severity of acute and chronic AIA, presumably by suppressing cell-mediated immunity against mBSA (the inducing antigen) and formation of autoantibodies. However, because of the fundamentally different DHEA physiology in rodents, the role of such a replacement therapy in human RA deserves further elucidation.

Chlamydia pneumoniae Infection and Inflammation in Adults with Asthma

Background:Chlamydia pneumoniae infection and immune response to the C. pneumoniae heat shock protein 60 (CpHsp60) have been suggested to be associated with asthma. Objectives: To study whether a slightly elevated C-reactive protein (CRP) level as a marker of low-grade systemic inflammation has a role in this association, we collected serum and sputum samples from 103 asthma patients with disease severity ranging from mild to moderate and from 30 healthy volunteers. Methods: IgA and IgG antibodies to C. pneumoniae elementary bodies (CpEB) and CpHsp60 were measured by enzyme immunoassay. Serum CRP levels were measured with a rapid two-site ultra-sensitive assay based on time-resolved immunofluorometry. Results: The asthma patients, especially those with moderate asthma, had higher serum IgA antibody levels to CpHsp60 than the healthy controls (test for trend, p = 0.05), whereas antibody levels to CpEB antigen did not differ between the study groups. CRP levels were higher in both asthma groups compared to the control group and moreover, the patients with moderate asthma had higher CRP levels than those with mild asthma (test for trend, p < 0.01). The subjects with a slightly elevated CRP level, defined as ≧1.8 mg/l, had higher CpEB IgA (p = 0.001), CpEB IgG (p = 0.008) and CpHsp60 IgA (p = 0.023) antibody levels in serum compared to the subjects with lower CRP levels. Conclusions: Slightly elevated CRP levels as a marker of low-grade systemic inflammation may be associated with C. pneumoniae infection in asthma patients.