Immune-Mediated Aggravation of the Campylobacter concisus-Induced Epithelial Barrier Dysfunction

Campylobacter concisus is a human-pathogenic bacterium of the gastrointestinal tract. This study aimed at the contribution of the mucosal immune system in the context of intestinal epithelial barrier dysfunction induced by C. concisus. As an experimental leaky gut model, we used in vitro co-cultures of colonic epithelial cell monolayers (HT-29/B6-GR/MR) with M1-macrophage-like THP-1 cells on the basal side. Forty-eight hours after C. concisus infection, the decrease in the transepithelial electrical resistance in cell monolayers was more pronounced in co-culture condition and 22 ± 2% (p < 0.001) higher than the monoculture condition without THP-1 cells. Concomitantly, we observed a reduction in the expression of the tight junction proteins occludin and tricellulin. We also detected a profound increase in 4 kDa FITC-dextran permeability in C. concisus-infected cell monolayers only in co-culture conditions. This is explained by loss of tricellulin from tricellular tight junctions (tTJs) after C. concisus infection. As an underlying mechanism, we observed an inflammatory response after C. concisus infection through pro-inflammatory cytokines (TNF-α, IL-1β, and IL-6) released from THP-1 cells in the co-culture condition. In conclusion, the activation of subepithelial immune cells exacerbates colonic epithelial barrier dysfunction by C. concisus through tricellulin disruption in tTJs, leading to increased antigen permeability (leaky gut concept).

In planta expression of nanobody-based designer chicken antibodies targeting Campylobacter

Campylobacteriosis is a widespread infectious disease, leading to a major health and economic burden. Chickens are considered as the most common infection source for humans. Campylobacter mainly multiplies in the mucus layer of their caeca. No effective control measures are currently available, but passive immunisation of chickens with pathogen-specific maternal IgY antibodies, present in egg yolk of immunised chickens, reduces Campylobacter colonisation. To explore this strategy further, anti-Campylobacter nanobodies, directed against the flagella and major outer membrane proteins, were fused to the constant domains of chicken IgA and IgY, combining the benefits of nanobodies and the effector functions of the Fc-domains. The designer chimeric antibodies were effectively produced in leaves of Nicotiana benthamiana and seeds of Arabidopsis thaliana. Stable expression of the chimeric antibodies in seeds resulted in production levels between 1% and 8% of the total soluble protein. These in planta produced antibodies do not only bind to their purified antigens but also to Campylobacter bacterial cells. In addition, the anti-flagellin chimeric antibodies are reducing the motility of Campylobacter bacteria. These antibody-containing Arabidopsis seeds can be tested for oral passive immunisation of chickens and, if effective, the chimeric antibodies can be produced in crop seeds.

Immune response-eliciting exposure to Campylobacter vastly exceeds the incidence of clinically overt campylobacteriosis but is associated with similar risk factors: A nationwide serosurvey in the Netherlands

BACKGROUND

We aimed to estimate population-level exposure to Campylobacter and associated risk factors, using three approaches for serological data analysis.

METHODS

Nationwide, population-based serosurvey in the Netherlands (Feb 2006-Jun 2007). Anti-Campylobacter IgG, IgM and IgA were measured using ELISA, and analysed via: a) seroincidence estimation, using reference values of antibody peak levels and decay rates over-time after Campylobacter exposure; b) two normal distributions of true positives/negatives fitted to the IgG distribution to derive seroprevalence and individual probability of being positive/negative; and c) IgG levels. Risk factors were analysed using multiple linear regressions.

RESULTS

From 1559 respondents, seroincidence was estimated at 1.61 infections/person-year (95%CI:1.58-1.64) and seroprevalence at 68.1% (65.4-70.9). The three approaches identified similar risk factors, although seroincidence had higher power and results were interpretable as risk: seroincidence was higher in females [exp(b) = 1.07(1.04-1.11)], older ages [vs. 15-34 years; for < 5, 5-14, 35-54 and 55-70 years: 0.60(0.58-0.63), 0.74(0.71-0.78), 1.08(1.03-1.13) and 1.08(1.01-1.16), respectively], non-Dutch background [Moroccan/Turkish: 1.25(1.14-1.37); Caribbean: 1.14(1.03-1.25)], low socioeconomic status [1.05(1.01-1.10)], traveling outside Europe [1.05(1.01-1.09)], and eating undercooked meat [1.04(1.01-1.08)].

CONCLUSION

Campylobacter exposure is much higher than clinical infection rates, but risk factors are similar to those previously described.Seroincidence is a powerful measure to study Campylobacter epidemiology, and is preferred over other methods.

Promising new vaccine candidates against Campylobacter in broilers

Campylobacter is the leading cause of human bacterial gastroenteritis in the European Union. Birds represent the main reservoir of the bacteria, and human campylobacteriosis mainly occurs after consuming and/or handling poultry meat. Reducing avian intestinal Campylobacter loads should impact the incidence of human diseases. At the primary production level, several measures have been identified to reach this goal, including vaccination of poultry. Despite many studies, however, no efficient vaccine is currently available. We have recently identified new vaccine candidates using the reverse vaccinology strategy. This study assessed the in vivo immune and protective potential of six newly-identified vaccine antigens. Among the candidates tested on Ross broiler chickens, four (YP_001000437.1, YP_001000562.1, YP_999817.1, and YP_999838.1) significantly reduced cecal Campylobacter loads by between 2 and 4.2 log10 CFU/g, with the concomitant development of a specific humoral immune response. In a second trial, cecal load reductions results were not statistically confirmed despite the induction of a strong immune response. These vaccine candidates need to be further investigated since they present promising features.

[Evaluation of a Newly Developed Campylobacter Antigen Detection Kit for Patients with Enteritis]

The newly developed rapid diagnostic test (RDT, DK14-CA1, Denka Seiken Co., Ltd.) to detect Campylobacter antigen was evaluated using fecal specimens of patients with enteritis. The RDT is an immunochromatographic assay using colored latex and can detect Campylobacter antigen (C. jejuni and C. coli) from patients' stool samples within 15 minutes. A total of 227 stool samples obtained from patients with enteritis were examined and the results were compared with conventional culture methods. Overall sensitivity, specificity, accuracy and positive predictive value (PPV) were 75.6%, 98.6%, 89.9% and 97.0% respectively. Among 53 severe cases defined with their clinical findings, sensitivity, specificity, accuracy and PPV were 82.1%, 100%, 90.6% and 100% respectively. Mean time to obtain the result with the RDT was 7 minutes whereas the culture method took 2.2 days. This study revealed the usefulness of the newly developed RDT as a rapid detection tool for Campylobacter antigen. Although the RDT has a little lower sensitivity compared with culture method, the simple and rapid test can contribute to treatment decisions for patients with enteritis and can be used at the patient's bedside and in outpatient clinics.

Oxidative and nitrosative stress defences of Helicobacter and Campylobacter species that counteract mammalian immunity

Helicobacter and Campylobacter species are Gram-negative microaerophilic host-associated heterotrophic bacteria that invade the digestive tract of humans and animals. Campylobacter jejuni is the major worldwide cause of foodborne gastroenteritis in humans, while Helicobacter pylori is ubiquitous in over half of the world's population causing gastric and duodenal ulcers. The colonisation of the gastrointestinal system by Helicobacter and Campylobacter relies on numerous cellular defences to sense the host environment and respond to adverse conditions, including those imposed by the host immunity. An important antimicrobial tool of the mammalian innate immune system is the generation of harmful oxidative and nitrosative stresses to which pathogens are exposed during phagocytosis. This review summarises the regulators, detoxifying enzymes and subversion mechanisms of Helicobacter and Campylobacter that ultimately promote the successful infection of humans.

Varying antibody responses of laying hens housed in an aviary system and in furnished cages

Antibody titers after vaccination against Infectious Bronchitis Virus (IBV), Newcastle Disease Virus (NDV) and after natural infection with Campylobacter were analyzed in five trials with Lohmann Silver laying hens kept in two different housing systems. In these studies it could be demonstrated that antibodies against IBV and Campylobacter were in 4 out of 5 respectively in 2 out of 5 trials significantly higher in hens housed in an aviary system compared to those kept in furnished cages. The opposite trend was observed for antibodies against NDV which were on average significantly higher in cages. The mean mortality rate was slightly higher in hens kept in the aviary system compared to the cage system.

Interactions between gastric and enteric infections: clues to the pathogenesis of inflammatory bowel disease?

Whereas the worldwide incidence of Crohn's disease (CD) continues to rise, Maori and Pacific Islanders living in New Zealand remain largely unaffected. The reason for this is currently unknown but may be linked to emerging evidence suggesting a role for Campylobacter spp in the aetiology of CD. Rates of campylobacteriosis are notably lower among Maori and Pacific Islanders and while this may reflect poorer access to primary care and diagnostic services, resulting in lower rates of notified disease, we consider it may also reflect a level of protective immunity in Maori and Pacific Islanders as a result of chronic infection from an early age with the closely related gastric pathogen Helicobacter pylori. Understanding the interactions between these antigenically-related bacteria may provide us with clues that ultimately help unravel the complex aetiology of CD.

Do patients with recurrent episodes of campylobacteriosis differ from those with a single disease event?

BACKGROUND

Although Campylobacter is the leading cause of reported bacterial gastro-enteritis in industrialized countries, little is known on its recurrence. The objective of this study is to describe the risk and the patient characteristics of recurrent episodes of human campylobacteriosis reported in Quebec.

METHODS

Laboratory-confirmed cases of campylobacteriosis reported in the province of Quebec, Canada, through ongoing surveillance between 1996 and 2006 were analyzed. The risk of having a recurrent episode of campylobacteriosis was described using life table estimates. Logistic regression was used to assess if gender, age and patient residential location were associated with an increased risk of recurrence.

RESULTS

Compared to the baseline risk, the risk for a recurrent disease event was higher for a period of four years and followed a decreasing trend. This increased risk of a recurrent event was similar across gender, but higher for people from rural areas and lower for children under four years of age.

CONCLUSIONS

These results may suggest the absence of durable immunity or clinical resilience following a first episode of campylobacteriosis and periodical re-exposure, at least among cases reported through the surveillance system.

Campylobacter-induced interleukin-8 responses in human intestinal epithelial cells and primary intestinal chick cells

Campylobacter (C.) jejuni and C. coli can cause gastrointestinal disorders in humans characterized by acute inflammation. Inflammatory signals are initiated during interaction between these pathogens and human intestinal cells, but nothing is known about the stimulation of avian intestinal cells by Campylobacter. Interleukin-8 (IL-8) as a proinflammatory chemokine plays an important role in mobilizing cellular defence mechanism. IL-8 mRNA expression in both human intestinal cells (INT 407) and primary intestinal chick cells (PIC) was determined by quantitative real-time RT-PCR. The secretion of IL-8 protein by INT407 was measured using ELISA. Although C. jejuni and C. coli are considered to be harmless commensals in the gut of birds, the avian Campylobacter isolates investigated were able to induce the proinflammatory IL-8 in PIC as well as in INT407. In an in vitro system, C. jejuni as well as C. coli were able to induce IL-8 mRNA in PIC. Relation between the virulence properties like toxin production, the ability to invade and to survive in Caco-2 cells and the level of IL-8 mRNA produced by INT 407 and PIC after infection with Campylobacter strains was also investigated.

Validation of an ELISA for the diagnosis of recent Campylobacter infections in Guillain–Barré and reactive arthritis patients

Weeks or months following Campylobacter infection, a small proportion of infected individuals develop Guillain-Barré syndrome (GBS) or reactive arthritis (ReA). Stool culture for Campylobacter is often negative in these patients, and serology is therefore the method of choice for diagnosing a recent infection with Campylobacter. This study developed a capture ELISA system to detect anti-Campylobacter IgA and IgM antibodies indicative of a recent infection. The sensitivity of the assay was 82.0% in uncomplicated Campylobacter enteritis patients, 96.2% in GBS patients who were culture-positive for Campylobacter, and 93.1% in culture-positive ReA patients, with a specificity of 93.0%. The assay allows identification of Campylobacter infection in patients with post-infectious neurological and rheumatological complications.

Vaccination of chickens against Campylobacter

The gram-negative bacterium Campylobacter is the leading cause of bacterial entero-colitis in humans and is associated with the occurrence of life-threatening auto-immune based neurological disorders. Chickens, which are often heavily colonized with Campylobacter without signs of pathology, are considered the most important source for human infection. Although vaccination is a well established and effective method to combat various microbes in poultry, a commercial vaccine against Campylobacter has not yet been developed. For the development of such a vaccine, three main challenges can be identified: (1) the identification of novel cross-protection-inducing antigens, (2) the induction of a rapid, potent immune response, and (3) the development of novel adjuvants to further stimulate immunity against Campylobacter. The rapidly emerging knowledge of the biology of Campylobacter in combination with the recent advances in the fields of molecular vaccinology and immunology provide the required setting for the development of an effective vaccine against Campylobacter in poultry.

Survey of campylobacter, salmonella and mycoplasmas in house crows (Corvus splendens ) in Malaysia

House crows (Corvus splendens) in Selangor, Malaysia were examined for the presence of Campylobacter species, Salmonella species, Mycoplasma gallisepticum and Mycoplasma synoviae by serology, culture and pcr. For the detection of Campylobacter and Salmonella species swabs were taken either from the intestine or cloaca. For the detection of mycoplasmas, swabs were taken either from the choanal cleft or trachea for culture and pcr and serum samples were tested by the rapid serum agglutination (rsa) and monoclonal antibody-blocking elisa (mbelisa) for antibodies to M gallisepticum and M synoviae. For campylobacter, 25.3 per cent of the crows were positive by culture, and the species identified were Campylobacter jejuni and Campylobacter coli. No Salmonella species were isolated. Four of 24 swabs were positive for M gallisepticum dna but none gave positive results for M synoviae dna. No M gallisepticum or M synoviae antibodies were detected by rsa but 60 per cent of the sera gave positive reactions for M gallisepticum and 13 per cent gave positive reactions for M synoviae by mbelisa.

Immune responses to Campylobacter and serum autoantibodies in patients with complex regional pain syndrome

We hypothesised that some complex regional pain syndromes (CRPS) may have a postinfectious and/or autoimmune basis. Sera from 92 patients with CRPS and 92 controls were investigated for immunoreactivity to Campylobacter strains and to rodent tissues. Both IgA-antibodies to Campylobacter and tissue-specific reactivity were often present in patients with short disease duration (< or = 1.5 years). Patients with minimal preceding trauma had stronger nervous tissue-specific reactivity than other patients, regardless of disease duration. These results provide preliminary evidence for immune activation early in CRPS and, additionally, that patients with minimal trauma may comprise an autoimmune subgroup.

Vaccines against diarrheal diseases

At least 2 million persons succumb annually to enteric infection, and in countless other patients, diarrheal disease aggravates malnutrition and susceptibility to other infections. Prevention of enteric illness by virtue of improved hygiene and provision of sanitation and water treatment is impractical in most developing countries, where morbidity and mortality rates are highest. For this reason, development of vaccines against the most important gastrointestinal infections remains a high priority.

Sensitivity and specificity of serology in determining recent acute Campylobacter infection

BACKGROUND

The measurement of serum antibodies to Campylobacter spp. has been used to investigate links between prior Campylobacter infections and the development of Guillain-Barre syndrome and its variants. Little is known of the serum antibody response to acute infections in the short- or long-term.

AIMS

The aims of the present study were to investigate the normal serum response to an acute Campylobacter infection and the sensitivity and specificity of anti-Campylobacter antibodies in determining recent Campylobacter infection.

METHODS

An enzyme-linked immunosorbent assay (ELISA) method was used to measure serum anti-Campylobacter immunoglobulin G (IgG), IgA and IgM antibodies. Controls consisted of 420 blood donors without recent gastroenteritis, 25 patients with other gastrointestinal infections, 24 patients with neurological conditions not affecting the peripheral nerves and 19 patients with autoimmune disorders. Three patient groups were assessed: 99 patients with acute Campylobacter infections, all of whom were tested 3 weeks post-infection; 69 of these patients tested 3-6 months later; and 74 additional patients tested >20 months post-infection. Western blot analysis was performed on controls and patients with high titre anti-Campylobacter antibodies to assess for cross-reactivity and specificity.

RESULTS

Following acute infections, all antibody classes rose in the majority of but not in all patients, followed by decreasing titres that did not return to baseline levels. Sixteen per cent of enteritis cases did not demonstrate a rise in titres and 9% of cases had significant levels of antibodies >20 months post-infection. The ELISA used was shown to be highly specific for the detection of Campylobacter antibodies.

CONCLUSION

The use of Campylobacter-specific antibody levels as the sole marker of prior infection is an unreliable method of determining the association between Campylobacter infection and neurological disease.

Serological methods and selective agars to enumerate Campylobacter from broiler carcasses: data from inter- and intralaboratory analyses

Routine analytical means to estimate Campylobacter numbers per milliliter of carcass rinses are needed in high-sample-throughput poultry laboratories. We compared three serological confirmatory tests that were amenable to such a setting when used in conjunction with Campy-Line and Campy-Cefex Campylobacter selective agars. Pre- and post-chlorinated chiller carcass rinse samples were obtained and held on ice, then analyzed 24 h later in two separate laboratories. Presumptive counts on both pre- and postchiller samples from between laboratories on individual agars and between both agars were highly correlated. Agreement among the three serological tests was nearly complete. The use of a premeasured and dried latex anti-Campylobacter antibody agglutination test format was superior to that of either a liquid latex agglutination format or a direct phosphate-buffer microscopic technique in terms of practicality as was the inclusion of an unarmed latex control to detect auto agglutination. A routine procedure for Campylobacter level estimation was suggested. This procedure, when used in conjunction with a serological confirmatory step, should provide processors with a means to assess reductions in numbers per milliliter of carcass rinses versus strictly presence-absence testing.

New approaches to development of mucosal vaccine against enteric bacterial pathogens; preventing campylobacteriosis

Although vaccination, after having been more than 200 years in medical practice, has proven to be the most effective and the cheapest way to prevent infectious diseases, they remain still the main cause of human premature deaths. As many pathogens enter the human body through the mucosal surfaces, the mucosal way of immunization is considered to be the most promising strategy to decrease the number of human infections. Moreover, the oral delivery system eliminates the necessity of injection what is extremely important for pediatric immunization programs. However, most of recently constructed subunit vaccines based on purified bacterial/viral antigens are rather poorly immunogenic. This review presents some novel ways to enhance and modulate host immune responses by combining antigens with specific adjuvants or by employing specific delivery systems. We also discuss some recent technologies, based on mining the genomic sequences of bacterial pathogens, which accelarate and improve identification of new candidates for vaccine construction. As an example, we focus on the progress in the development of vaccine against Campylobacter spp. Campylobacter jejuni is now recognized as a leading cause of bacterial enteritis in human.

[Experience in the use of a new test system for the rapid indication of the causative agents of campylobacter infection under the conditions of an emergency situation]

A new test system on the basis of magnetoimmunosorbents for the rapid indication of capmpylobacteriosis has been developed. Information on its use under the conditions of emergency situations is presented. Good prospects of this new test system in the study of environmental objects have been demonstrated.

Helicobacter pylori and Campylobacter rectus share a common antigen

AIM

The aim of this study was to investigate the presence of antigens with immunological cross-reactivity in periodontopathogenic bacteria and Helicobacter pylori, the pathogen associated with gastritis and peptic ulcers in human.

MATERIALS AND METHODS/RESULTS

Among the putative periodontopathogens tested (Actinobacillus actinomycetemcomitans, Campylobacter rectus, Fusobacterium nucleatum, Porphyromonas gingivalis, Prevotella intermedia and Treponema denticola), cross-reactive bands were only detected in C. rectus by SDS-PAGE/Western immunoblotting analysis using a polyclonal antibody directed to H. pylori cells. One of these cross-reactive antigens, a 64-kDa band antigen, also reacted with a monoclonal antibody directed to the human heat shock protein (HSP) 60. The N-terminal amino acid sequence of this C. rectus protein revealed a high degree of homology with corresponding regions of other HSPs belonging to the HSP60 family, indicating that the 64-kDa antigen was a GroEL protein. The nucleotide sequence of the C. rectus GroEL protein coded for a 547 amino acid protein with a predicted size of 57.8 kDa. Comparison of the alignment of the deduced amino acid sequence of the GroEL protein of C. rectus with that of H. pylori showed a high degree of similarity throughout its length (76.8%). GroEL protein from C. rectus possessed the ability to stimulate production of IL-6 by a confluent monolayer of human gingival epithelial cells and was cytotoxic when used at a high concentration.

CONCLUSIONS

This study reveals an immunological relationship between H. pylori and C. rectus, and clearly indicates that one of the shared antigens is a GroEL protein possessing a biological activity that might play a role in the initiation and progression of periodontal disease.

Detection of Campylobacter rectus in periodontitis sites by monoclonal antibodies

Campylobacter rectus, a gram-negative, microaerophilic, and motile bacterium, has been proposed to play a pathogenic role in human periodontitis. Surface components, such as the flagellum, surface layer (S-layer), and cytotoxin, have been reported as possible virulence factors of the microorganism. In the present study, monoclonal antibodies against surface components of this bacterium were produced to detect and investigate the pathogenic potential of C. rectus in periodontitis. Two monoclonal antibodies, designated CRT-1 and CRT-2, recognized a peculiar 150 kDa S-layer protein by immunoblot analysis. The CRT-2 antibody reacted to all C. rectus strains tested, except for the S-layer negative strain of the species [C. rectus ATCC 33238 S-layer (-) strain]. The CRT-3 antibody reacted to a 60-kDa protein in C. rectus and also cross-reacted with Campylobacter showae ATCC 51164 and CCUG 11641 strains. Using the dot-blot method, we were able to detect C. rectus using the CRT-2 antibody when as few as 103 organisms were present in a subgingival dental plaque sample. Detection of C. rectus in plaque samples correlated significantly with clinical findings such as probing depth (P < 0.001), bleeding on probing (P < 0.001), and gingival index (P < 0.001). These findings indicate that infection by C. rectus may be an important indicator of periodontal disease status.

Ecological and immunopathological implications of oral bacteria in Helicobacter pylori-infected disease

Increasing evidence has linked colonization by Helicobacter pylori with the development of gastritis and peptic ulcer disease. H. pylori resides primarily in the gastric mucosa without invading the gastric epithelium, causing persistent mild gastric inflammation. There are many reports examining the relationship between colonization by microorganisms in the stomach and oral cavity. We found that some oral bacteria are able to trap H. pylori cells, but oral bacteria inhibit H. pylori growth in vitro. In cases where H. pylori was detected in oral cavity samples, including oral cancer surface samples, we suggested that this species had colonized the stomach and were present in the oral cavity only as a transient organism. We demonstrated that periodontopathic Campylobacter rectus strains posses proteinaceous antigens, including heat shock proteins that share antigenicity with antigens of H. pylori strains. These cross-reactive antigens between H. pylori and C. rectus may be related to the induction of immunopathological responses in periodontal tissues and the stomach. We concluded that H. pylori could not survive in the human oral cavity; however, there would be an interrelationship between periodontal disease due to C rectus and stomach diseases due to H. pylori.

IgG subclass specific antibody response to periodontopathic organisms in HIV-positive patients

BACKGROUND

We previously reported an increased rate of progression of periodontal disease over an 18-month period in human immunodeficiency virus (HIV)-positive subjects compared to controls. The mechanism for disease progression and rapid tissue loss was unknown. Data on the microbiological studies failed to show any significant difference in the microbial characteristics of the periodontal lesions in HIV-positive patients compared to HIV-negative controls. Immunological analysis had identified neutrophils as an important component of the host defense against periodontal infection, especially against rapid tissue loss. Serum IgG reactivities to periodontal pathogens in HIV-positive patients with periodontitis were reduced. Other data provided circumstantial evidence to suggest that IgG subclass (IgG2) specific antibody might assist bacterial clearing in periodontal infection. The aim of the current study was to examine the specific IgG subclass antibody response to a panel of periodontopathic organisms: Actinobacillus actinomycetemcomitans (Aa), Porphyromonas gingivalis (Pg), Prevotella Intermedia (Pi), Fusobacterium nucleatum (Fn), Campylobacter rectus (Cr), and Bacteroides forsythus (Bf) in HIV-positive patients compared to HIV-negative controls.

METHODS

Sera from 120 HIV-positive patients (40 periodontitis, 69 gingivitis, and 11 no oral diseases) were tested for IgG subclass specific antibody response to the above listed 6 organisms using enzyme-linked immunosorbent assay. Data were compared with those obtained from 40 HIV-negative control subjects (35 periodontitis, 2 gingivitis, and 3 no oral diseases).

RESULTS

In the HIV-positive group, a consistently high response rate was found in IgG1 to all the bacteria tested. In addition, high levels of IgG3 and IgG4 to Pg and IgG1 and IgG2 to Pi were also present. However, no significant difference was detected among the periodontitis, gingivitis, and no oral disease subgroups. When the periodontitis patients from the HIV-positive group were compared to the HIV-negative group, no difference in the antibody levels and response rates was noted.

CONCLUSION

We conclude that in HIV-positive patients, the specific IgG subclass antibody response to periodontopathic organisms was similar to that of HIV-negative subjects.

Serum markers of periodontal disease status and inflammation in hemodialysis patients

BACKGROUND

Hemodialysis (HD) patients face a 25% annual mortality rate, with 50% of reported deaths attributed to cardiovascular disease. All-cause and cardiovascular mortality correlate with such acute-phase proteins as C-reactive protein (CRP). Hepatic CRP synthesis is upregulated by inflammation; however, elevated CRP values frequently are found in the absence of apparent infection or inflammation. Because destructive periodontal diseases have been associated with elevated CRP levels, we questioned whether destructive periodontal diseases could contribute to elevated CRP values in HD populations.

METHODS

Sera from 86 consecutive dentate HD patients were assayed for levels of immunoglobulin G (IgG) antibody to six periodontal species by means of an enzyme-linked immunosorbent assay.

RESULTS

CRP values for the subject population ranged from less than 6.9 to 159 mg/L (median, 8.2 mg/L). Univariate comparisons between subjects with or without elevated CRP levels (>10 mg/L) showed that CRP level elevation was associated significantly (P < 0.05) with greater doses of human recombinant erythropoietin and lower levels of hemoglobin, serum iron, transferrin saturation (TSat), albumin averaged over the 3 preceding months, total cholesterol, and triglycerides. Log serum IgG antibody levels to Porphyromonas gingivalis also were significantly greater in the group with elevated CRP levels (P = 0.013). Subsequent multivariate logistic regression showed that log serum antibody levels to P gingivalis remained significant (P = 0.02) after controlling for nonperiodontal sources of elevated CRP, hemoglobin, TSat, and triglyceride values.

CONCLUSION

These results suggest that elevated levels of IgG antibody to bacterial species associated with destructive periodontal diseases are associated with elevated CRP values in HD populations.

Occurrence and strain diversity of thermophilic campylobacters in cattle of different age groups in dairy herds

AIMS

To investigate the occurrence and numbers of thermophilic campylobacters excreted by cattle in dairy herds, and to assess the strain diversity within herds.

METHODS AND RESULTS

Faecal samples from 15 animals at each of 24 cattle farms were cultured quantitatively for thermophilic campylobacters and 23% of animals and 83% of farms were positive for Campylobacter jejuni. Young animals had a higher prevalence and higher faecal concentration than older animals. Serotyping and pulsed field gel electrophoresis (PFGE) of isolates showed that the most common serotypes were 2, 4-complex and 11. Serotype 2 was especially prevalent among calves (68% of the positive calves). In eight of the 20 positive herds, all isolates had the same sero- and PFGE type while, in the other herds, two to five different types were isolated.

CONCLUSIONS

Significant differences were found between age groups in relation to the prevalence and numbers of excreted campylobacters, serotype distribution and strain diversity. The relatively few different strains in each herd indicate that transmission between animals is common.

SIGNIFICANCE AND IMPACT OF THE STUDY

The high prevalence on cattle farms of the human pathogen C. jejuni and the wide distribution of serotype 2, the most common serotype among Danish patients, indicate that cattle might be an important reservoir for human infections. The ability of this serotype to colonize calves in high numbers further indicates that serotype 2 strains may have an advantage over other serotypes.

Serum IgG antibody response to periodontal pathogens in minority populations: relationship to periodontal disease status and progression

Differences in periodontal disease prevalence, severity, subgingival microflora and host immune response have been reported for various ethnic/racial groups, which implies that risk factors for destructive periodontal disease progression may also vary in these populations. As it is possible that these differences may be due to confounding variables other than ethnicity/race, we have measured serum IgG antibody response to six periodontal pathogens, and compared these data with microbiological, clinical and demographic parameters in three urban minority populations. The study population consisted of 23 Asiatic, 48 African-American and 37 Hispanic subjects, who were resident in the greater New York region. Clinical indices that were recorded included pocket depth, attachment level, gingival erythema, bleeding upon probing, suppuration and supragingival plaque. Attachment level measurements were taken twice at each visit, and the difference between the means of pairs of measurements taken at baseline and two months later was used to determine disease progression. Subgingival microbiological species were identified and enumerated using DNA-DNA checkerboard hybridization. Serum IgG antibody levels to Actinobacillus actinomycetemcomitans serotyopes a and b, Bacteroides forsythus, Campylobacter rectus, Porphyromonas gingivalis and Prevotella intermedia were measured by enzyme-linked immunosorbant assay (ELISA). Mean serum IgG antibody to P. gingivalis was found to be higher in the African-American group, while IgG antibody to B. forsythus was lower in the Hispanic group. However, the African-American group also had greater mean probing depth, attachment loss, number of missing teeth and numbers of individuals within the unskilled occupational group. When the data were analyzed by occupational status, mean serum IgG antibody to P. gingivalis increased from professional to skilled to unskilled groups. For the entire study population, prior disease and subsequent attachment loss were associated with elevated serum IgG antibody to P. gingivalis. Increasing pocket depth, attachment level, gingival erythema and age were also positively correlated with serum IgG antibody to P. gingivalis, but not with serum IgG antibody to the other five subgingival species. No correlation was found between whole-mouth bacterial levels and homologous serum IgG antibody levels. These results suggest that elevated serum IgG antibody to P. gingivalis reflects destructive periodontal disease status, and may be considered a risk factor for disease progression in these ethnic/racial populations. In addition, although differences in serum IgG antibody profiles to subgingival species were found among the three ethnic/racial groups, environmental and socioeconomic variables may have a greater influence on serum IgG antibody levels in these populations.

Parotid salivary S-IgA antibodies during experimental gingivitis in smokers and non-smokers

Persons who smoke display a less pronounced increase of gingival bleeding in the experimental gingivitis model as compared with non-smokers. The aim of the present study was to investigate whether this could partly be explained by differences in levels of parotid total secretory IgA (S-IgA) or parotid S-IgA reactive with selected oral microorganisms. Parotid saliva samples were obtained from 11 smoking and 14 non-smoking volunteers, at baseline, after 5 and 14 days of full mouth experimental gingivitis. Output levels of total S-IgA and of specific S-IgA reactive with cell extracts from Actinobacillus actinomycetemcomitans, Actinomyces naeslundii, Campylobacter rectus, Fusobacterium nucleatum, Porphyromonas gingivalis, Prevotella intermedia, Prevotella nigrescens, Peptostreptococcus micros, Streptococcus gordonii and Streptococcus mutans were determined in the samples by means of ELISA. Smokers and non-smokers were found to have similar output levels (microg/min) of total S-IgA, and the values did not significantly change during the experimental gingivitis trial. Parotid salivary outputs (units/min) of the bacteria-specific S-IgA at baseline and at days 5 and 14, were not different between smokers and non-smokers; no changes were observed during the experimental gingivitis trial. The present observations indicate that total S-IgA and bacteria-specific S-IgA in saliva are not main factors that can explain the less pronounced increase of gingival bleeding in the experimental gingivitis model in smokers as compared with non-smokers.

Antigenic properties of the GroEL-like protein of Campylobacter rectus

The purpose of this study was to clarify the antigenic properties of the GroEL-like protein of Campylobacter rectus using a specific polyclonal antibody directed to the purified 64-kDa GroEL-like protein (pAb-CrGroEL), a polyclonal antibody directed to the Actinobacillus actinomycetemcomitans GroEL-like protein (pAb-AaGroEL) and a monoclonal antibody against the recombinant human HSP60 (mAb-HuHSP60). In SDS-PAGE/Western immunoblotting analysis, mAb-HuHSP60, pAb-CrGroEL and pAb-AaGroEL were found to react with the GroEL-like protein (64-kDa) present in all C. rectus strains. A 150-kDa protein in C. rectus ATCC 33238 also reacted strongly with pAb-CrGroEL. This 150-kDa protein was found to be present on the surface-associated material of bacterial cells, as determined by transmission electron microscopy and immunogold labelling of cells with pAb-CrGroEL. Analysis of the first 20 N-terminal amino acids of the sequence of the 150-kDa protein revealed a strong homology (80%) with the C. rectus surface layer (S-layer) protein. Investigation of the biochemical nature of antigenic determinants using periodic acid and proteolytic enzymes showed that the C. rectus GroEL-like protein possessed immunodominant epitopes in both peptide and carbohydrate chains, and that the immunoreactive determinants of the 150-kDa protein belonged to carbohydrate. These results suggest that the GroEL-like protein and the S-layer protein of C. rectus may share the same carbohydrate epitopes.

Maternal periodontitis and prematurity. Part II: Maternal infection and fetal exposure

Clinical data from the first 812 deliveries from a cohort study of pregnant mothers entitled Oral Conditions and Pregnancy (OCAP) demonstrate that both antepartum maternal periodontal disease and incidence/progression of periodontal disease are associated with preterm birth and growth restriction after adjusting for traditional obstetric risk factors. In the current study we present measures of maternal periodontal infection using whole chromosomal DNA probes to identify 15 periodontal organisms within maternal periodontal plaque sampled at delivery. In addition, maternal postpartum IgG antibody and fetal exposure, as indexed by fetal cord blood IgM level to these 15 maternal oral pathogens, was measured by whole bacterial immunoblots. The potential role of maternal infection with specific organisms within 2 bacterial complexes most often associated with periodontitis, conventionally termed "Orange" (Campylobacter rectus, Fusobacterium nucleatum, Peptostreptococcus micros, Prevotella nigrescens, and Prevotella intermedia) and "Red" (Porphyromonas gingivalis, Bacteroides forsythus, and Treponema denticola) complexes, respectively, to prematurity was investigated by relating the presence of oral infection, maternal IgG, and fetal cord IgM, comparing full-term to preterm (gestational age < 37 weeks). The prevalence of 8 periodontal pathogens was similar among term and preterm mothers at postpartum. There was a 2.9-fold higher prevalence of IgM seropositivity for one or more organisms of the Orange or Red complex among preterm babies, as compared to term babies (19.9% versus 6.9%, respectively, P = 0.0015, chi square). Specifically, the prevalence of positive fetal IgM to C. rectus was significantly higher for preterm as compared to full-term neonates (20.0% versus 6.3%, P = 0.0002, as well as P. intermedia (8.8% versus 1.1%, P = 0.0003). A lack of maternal IgG antibody to organisms of the Red complex was associated with an increased rate of prematurity with an odds ratio (OR) = 2.2; confidence interval (CI) 1.48 to 3.79), consistent with the concept that maternal antibody protects the fetus from exposure and resultant prematurity. The highest rate of prematurity (66.7%) was observed among those mothers without a protective Red complex IgG response coupled with a fetal IgM response to Orange complex microbes (combined OR 10.3; P < 0.0001). These data support the concept that maternal periodontal infection in the absence of a protective maternal antibody response is associated with systemic dissemination of oral organisms that translocate to the fetus resulting in prematurity. The high prevalence of elevated fetal IgM to C. rectus among premature infants raises the possibility that this specific maternal oral pathogen may serve as a primary fetal infectious agent eliciting prematurity.

Associations between serum antibody levels to periodontal pathogens and early-onset periodontitis

BACKGROUND

The role of antibodies to periodontal microorganisms in the development of periodontal tissue destruction is still unclear. The aim of this study was to investigate the association between serum levels of IgG, IgA, and IgM antibodies to 6 periodontal microorganisms and clinical subtypes of varying severity of early-onset periodontitis (EOP) in young African American adults.

METHODS

The study group consisted of 159 African Americans aged 19 to 25 years (mean 22 years) and included 97 cases with EOP and 62 controls with no clinical signs of EOP. These subjects were selected from a nationally representative sample of adolescents who received an oral examination as part of the National Survey of Oral Health of United States Children in 1986-1987. The group was examined clinically a second time 6 years later and blood samples were collected. Serum levels of IgG, IgA, and IgM reactive to Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis, Prevotella intermedia, Campylobacter rectus, Eikenella corrodens, and Fusobacterium nucleatum were assessed.

RESULTS

Serum levels of IgG and IgA antibody reactive to P. gingivalis and A. actinomycetemcomitans and IgA antibody to P. intermedia were significantly higher in generalized EOP cases compared to healthy controls. IgM antibody levels did not show any significant associations with EOP for any of the 6 bacterial species tested. There were no significant differences in antibody levels between controls and the 13 subjects in our study who were classified with localized EOP.

CONCLUSIONS

The findings suggest that antibodies to P. gingivalis, P. intermedia, and A. actinomycetemcomitans may play a significant role in the pathogenesis of EOP. Substantial longitudinal studies that monitor antibody levels and avidity prior to disease onset, during progression, and following clinical intervention will be necessary to fully understand the role of this component of the immune response in protection versus tissue destruction and the potential use in EOP risk assessment and disease management.

Guillain-Barré syndrome serum and anti-Campylobacter antibody do not exacerbate experimental autoimmune neuritis

To investigate whether antibodies are pathogenic in Guillain-Barré syndrome (GBS), we injected pre-treatment serum from 11 GBS patients intraperitoneally into rats in which the blood-nerve barrier had been opened by induction of mild adoptive transfer experimental autoimmune neuritis. There was no significant clinical, neurophysiological or pathological difference between rats receiving GBS serum compared with those receiving control serum, except that GBS serum caused minor excess weight loss. Murine monoclonal antibody to Campylobacter jejuni and gangliosides also did not exacerbate disease. This experiment failed to show antibody-mediated disease exacerbation and so does not support an antibody-mediated mechanism in GBS.

Genomic heterogeneity and O-antigenic diversity of Campylobacter upsaliensis and Campylobacter helveticus strains isolated from dogs and cats in Germany

A serotyping scheme based on heat-stable surface antigens was established for 101 Campylobacter upsaliensis and 10 Campylobacter helveticus strains isolated from 261 dogs and 46 cats of different ages originating from two geographically distinct regions in Germany. The prevalence of C. upsaliensis varied between 27.8% in juvenile dogs (<12 months of age) and 55.4% in adult dogs (P < 0.05). Of the cats, 19.6% harbored C. upsaliensis, whereas 21.7% carried C. helveticus. Of the C. upsaliensis isolates from both host species, 93.1% belonged to five different serogroups, two of them being prevalent at rates of 47.5 and 27.7%, with different frequencies in both regions. Six (54.6%) of the C. helveticus isolates also belonged to serotypes found among C. upsaliensis strains, whereas five (45.4%) possessed an O antigen unique for C. helveticus. In contrast, a considerable degree of genomic diversity of the isolates was assessed by macrorestriction analyses with the endonucleases SmaI and XhoI, using pulsed-field gel electrophoresis as well as enterobacterial repetitive intergenic consensus sequence PCR (ERIC PCR). Restriction with SmaI pointed towards the existence of clonal groups associated to some extent with serotypes, while restriction with XhoI disintegrated these groups to smaller noncoherent subgroups. Analysis of ERIC PCR profiles did not exhibit any associations with serotypes. In conclusion these data demonstrate the genomic heterogeneity among C. upsaliensis strains and indicate that the combination of SmaI restriction with serotyping is a useful tool to investigate the expansion of clonal groups of C. upsaliensis.

Serum phenytoin concentration and IgG antibody titre to periodontal bacteria in patients with phenytoin-induced gingival overgrowth

Epileptic patients taking phenytoin with gingival-overgrowth and those without gingival-overgrowth were compared for daily drug dose, plasma total phenytoin concentration, plasma free-phenytoin concentration and serum IgG antibody titre against 13 periodontal bacteria. Significantly higher daily drug dose was noted in patients with gingival overgrowth (P < 0.05) when compared with those without overgrowth. In addition, both total and free forms of plasma phenytoin concentration were significantly higher in sera of patients with gingival growth than of those without overgrowth (P < 0.01). Strong positive correlation was found between daily drug dose and serum phenytoin concentration in patients with gingival overgrowth, while weak correlation was found in patients without gingival overgrowth, suggesting a difference in drug metabolism in these two groups. However, no differences were found in serum IgG antibody titres to 13 periodontal bacteria examined between two groups. These results suggest that metabolic ability of phenytoin is one of the factors for developing gingival overgrowth, and that periodontal infection may not be a primary causative factor for gingival overgrowth but act as an additive factor which increase tissue mass for this unwanted side effect.

Shared antigenicity between Helicobacter pylori and periodontopathic Campylobacter rectus strains

Periodontopathic Campylobacter rectus strains possess 41- and 68-kDa proteinaceous antigens which share antigenicity with antigens of Helicobacter pylori strains. H. pylori strains have a 54-kDa antigen which reacts with C. rectus strains. We found that the salivary IgA levels against H. pylori were correlated with those against C. rectus. These cross-reactive antigens of C. rectus may affect the serological diagnosis of H. pylori infections, especially when saliva is used. It is possible that these cross-reacting antigens may relate to the induction of immunopathological responses against both microorganisms.

Periodontal Findings and Systemic Antibody Responses to Oral Microorganisms in Behçet's Disease

BACKGROUND

Behçet's disease is a multisystem disorder of unknown etiology, affecting predominantly the oral mucosa, skin, and eyes. Recurrent and painful episodes of oral ulcerations interfere with regular oral hygiene leading to rapid bacterial plaque accumulation. The aims of this study were to evaluate the periodontal status of patients with Behçet's disease and determine serum antibody responses to selected oral microorganisms, including major periodontopathogens in these patients.

METHODS

Thirty-three patients with Behçet's disease and 15 healthy subjects were included in the study. Plaque, sulcular bleeding, periodontal index scores, probing depths, and total number of teeth were recorded. Serum IgG antibody levels to a panel of 13 oral microorganisms were determined.

RESULTS

Significantly higher values for each of the clinical measures were observed in patients with Behçet's disease compared to healthy subjects (P <0.0001). Antibody levels to selected members of plaque, including Actinomyces viscosus, Streptococcus mutans, Streptococcus sanguis, Streptococcus oralis, Eikenella corrodens, Campylobacter rectus, and Prevotella intermedia were significantly lower in patients with Behçet's disease than in controls (P <0.001-0.05). In contrast, these patients exhibited significantly elevated antibody levels to Actinobacillus actinomycetemcomitans Y4 compared to controls (P <0.01).

CONCLUSIONS

Our data indicate that the patients with Behçet's disease generally exhibit clinical findings of established periodontal disease. Decreased antibody responses to early colonizers of both supra- and subgingival plaque were observed along with the elevation in antibody levels to A. actinomycetemcomitans. These results suggest that the bacterial plaque ecology and/or immune responses to these microorganisms may be affected in Behçet's disease which could lead to changes in the expression of periodontal disease.

Analysis of serum antibody responses to periodontopathogens in early-onset periodontitis patients from different geographical locations

Serum antibody specificity to oral micro-organisms was used to delineate the pathogens associated with early-onset periodontal diseases in a Turkish population. Additionally, comparison of the findings to those derived from a clinically similar US patient population described differences in bacterial specific antibody between these 2 geographic regions. Serum from 89 (LJP), 86 (RPP) and 94 (normal) subjects was analyzed (ELISA) to determine IgG antibody to 14 oral micro-organisms. All LJP patients from Turkey exhibited elevated antibody levels to A. actinomycetemcomitans (serotypes c and a significantly increased), while antibody levels to A. actinomycetemcomitans Y4 and JP2 (serotype b) were significantly higher in US LJP patients. 50% of the Turkish RPP patients also showed elevated anti-A. actinomycetemcomitans antibody, although the US RPP patients exhibited significantly higher antibody levels and frequency of elevated antibody to the A. actinomycetemcomitans serotypes. Healthy subjects and LJP and RPP patients from the US exhibited higher antibody levels to all 3 P. gingivalis serogroups compared to those from Turkey, although, the frequency of elevated antibody to the P. gingivalis serogroups was significantly higher in LJP and RPP patients from Turkey than from the US. Interestingly, 87% and 77% of the LJP patients in the Turkish population had elevated antibody responses to P. gingivalis and E. corrodens, respectively, which was not observed in the US LJP patients. These data suggested that considerable variation exists in the systemic antibody levels to periodontopathogens between these 2 countries. This supports potential differences in subgingival colonization or antigenic composition of these pathogens between patient populations from different geographical regions.

The GroEL-like protein from Campylobacter rectus: immunological characterization and interleukin-6 and -8 induction in human gingival fibroblast

The native GroEL-like protein was purified from Campylobacter rectus, a putative periodontal pathogen, by affinity chromatography on ATP-agarose followed by high performance liquid chromatography on Superose 6. The purified 64-kDa protein (denatured form of GroEL-like protein) was immunoreactive by SDS-PAGE and Western immunoblotting with the monoclonal antibody directed against heat shock protein 60 of human origin. The native GroEL-like protein stimulated both interleukin-6 (IL-6) and IL-8 secretion by a confluent monolayer of human gingival fibroblast in their culture supernatant. During the 22-h incubation, the amounts of IL-6 and IL-8 were increased by 5.4- and 3.5-fold, respectively. These data suggested that the GroEL-like protein might be considered to be a virulence factor of C. rectus in periodontal disease.

Epidemiological typing of Campylobacter isolates from meat processing plants by pulsed-field gel electrophoresis, fatty acid profile typing, serotyping, and biotyping

Campylobacter spp. are a leading cause of bacterial gastroenteritis. Foods of animal origin, particularly under-cooked poultry, are common sources of Campylobacter species associated with disease in humans. A collection of 110 Campylobacter jejuni and 31 C. coli human and environmental isolates from different Ontario, Canada, abattoirs were analyzed by pulsed-field gel electrophoresis, fatty acid profile typing, and biotyping. Previously collected serotyping data for the same isolates were also analyzed in this study. Pulsed-field gel electrophoresis was found to be the most discriminatory of the typing methods, followed by serotyping, fatty acid profile typing, and biotyping. A wide variety of typing profiles were observed within the isolates, suggesting that several different Campylobacter sp. strains were present within the abattoirs.

Campylobacter species and Guillain-Barré syndrome

Since the eradication of polio in most parts of the world, Guillain-Barré syndrome (GBS) has become the most common cause of acute flaccid paralysis. GBS is an autoimmune disorder of the peripheral nervous system characterized by weakness, usually symmetrical, evolving over a period of several days or more. Since laboratories began to isolate Campylobacter species from stool specimens some 20 years ago, there have been many reports of GBS following Campylobacter infection. Only during the past few years has strong evidence supporting this association developed. Campylobacter infection is now known as the single most identifiable antecedent infection associated with the development of GBS. Campylobacter is thought to cause this autoimmune disease through a mechanism called molecular mimicry, whereby Campylobacter contains ganglioside-like epitopes in the lipopolysaccharide moiety that elicit autoantibodies reacting with peripheral nerve targets. Campylobacter is associated with several pathologic forms of GBS, including the demyelinating (acute inflammatory demyelinating polyneuropathy) and axonal (acute motor axonal neuropathy) forms. Different strains of Campylobacter as well as host factors likely play an important role in determining who develops GBS as well as the nerve targets for the host immune attack of peripheral nerves. The purpose of this review is to summarize our current knowledge about the clinical, epidemiological, pathogenetic, and laboratory aspects of campylobacter-associated GBS.

Nonlipopolysaccharide surface antigens of Campylobacter species

Among the protein antigens of Campylobacter species, flagellin, the subunit of the flagellar filament, is the best characterized. The motility imparted by this locomotory organelle is absolutely essential for Campylobacter organisms to colonize the gastrointestinal tract and to cause diarrheal disease. Flagellin is the immunodominant protein recognized during infection and has been suggested to be involved in the protective immune response. Campylobacter flagellins are glycosylated, which is an unusual posttranslational modification for prokaryotic proteins. Although the chemical structure of the glycosylated moiety is undetermined, the posttranslational modification includes sialic acid. The association of glycosylated flagellin with development of Guillain-Barré syndrome remains speculative, but the possibility of molecular mimicry between glycosylated flagellin and eukaryotic glycoproteins exists.

Expression of Campylobacter hyoilei lipo-oligosaccharide (LOS) antigens in Escherichia coli

Campylobacter spp. are well recognized as primary pathogens in animals and in people. To isolate and define the genetic regions encoding major surface antigens of Campylobacter hyoilei, genomic DNA of the type strain of the species, RMIT-32A, was cloned into a cosmid vector, pLA2917, in Escherichia coli and the resulting genomic library was screened using antiserum raised to the parent C. hyoilei strain. Six cosmid clones were found to express a series of immunoreactive bands in the 15-25 kDa range. These bands were proteinase K-resistant and were found in the LPS fraction of the cells, suggesting that the recombinant cosmids expressed C. hyoilei lipo-oligosaccharide (LOS) antigen(s). The minimum DNA insert size required for expression of C. hyoilei LOS antigen(s) in E. coli was 11.8 kb. This region was subcloned into the plasmid vector pBR322. The partial sequencing of the 11.8 kb region showed that it contains two ORFs, designated rfbF and rfbP, showing homology with the rfbF gene from Serratia marcescens and the rfbP gene from Salmonella typhimurium. Both genes are involved in LPS synthesis. The region also contained a sequence homologous to the rfaC gene of E. coli and Sal. typhimurium which is involved in core oligosaccharide synthesis.

Evidence for serum immunoglobulin G (IgG) antibody responses in Macaca fascicularis identified by monoclonal antibodies to human IgG subclasses

This investigation determined the capacity of murine monoclonal antibodies directed to human immunoglobulin G (IgG) subclasses to identify molecules with conserved epitopes in the serum of the nonhuman primate, Macaca fascicularis. We subsequently utilized this cross-reactivity to document the characteristics of IgG subclass antibody responses in M. fascicularis to parenteral immunization with intact oral microorganisms, antigens from oral microorganisms, and finally a defined protein toxin, tetanus toxoid. The IgG response in nonhuman primates immunized with tetanus toxoid showed a 40-fold and 110-fold increase after primary and secondary immunizations, respectively. The major IgG subclass responses were IgG1 and IgG3, with little, though significant, responses in the IgG4 and IgG2 subclasses. Seventy-five to 94% of the natural IgG antibody in nonhuman primate sera to Porphyromonas gingivalis, Prevotella intermedia and Campylobacter rectus was IgG1. IgG2 and IgG3 predominated to Bacteroides fragilis, IgG4 to Actinomyces viscosus and an equal distribution among the subclasses was noted in response to Fusobacterium nucleatum. Parenteral immunization of nonhuman primates with intact P. gingivalis elicited primarily IgG3 and IgG4, while the post-immunization IgG response to P. intermedia was largely IgG1. Nonhuman primates were also parenterally immunized with cell envelope antigens of P. gingivalis, P. intermedia, or a combination of cell envelope antigen from C. rectus and F. nucleatum and cell wall antigens of A. viscosus. The greatest IgG antibody response seen post-immunization was reactive with anti-human IgG1 for all of these antigens except to C. rectus which bound nonhuman primate antibody reactive with anti-human IgG2. It appears that the bacteria and their products exhibit unique differences in their induction of serum IgG subclass antibody responses. The characteristics of their immunogenicity as detected by the nonhuman primate may contribute to the ability of the immune responses to effectively interact with these pathogens.

Characteristics of systemic antibody responses of nonhuman primates to cell envelope and cell wall antigens from periodontal pathogens

The immune response of the primate, Macaca fascicularis, to cell envelope (CEA) or cell wall (CWA) antigens of several periodontal pathogens was examined to develop a strategy to interfere with ligature-induced periodontitis. Animals were parenterally immunized with CEA of either Porphyromonas gingivalis, Prevotella intermedia or a combination of CEA/CWA of Campylobacter rectus, Fusobacterium nucleatum and Actinomyces viscosus. Serum samples were taken every 2-4 weeks over a 4-month period, which included a 13-week interval with molar teeth ligated. All of the nonhuman primates in the study exhibited baseline levels of IgG, IgM and IgA antibody to formalinized whole cells of the bacteria. These levels increased significantly following immunization and were elevated above baseline throughout the remainder of the experiment. The largest change in antibody responses was seen in IgA antibody levels of P. gingivalis and C. rectus (42-fold above baseline), IgM antibody to P. intermedia, (41-fold increase) and IgG antibody to F. nucleatum and A. viscosus (32 and 63-fold increases). Moreover, the nonhuman primates exhibited differences in isotype response levels to whole microorganisms compared with the cell envelope antigens. These findings demonstrate the capacity of these nonhuman primates to produce an active immune response to microorganisms chronically colonizing the subgingival microbiota. Additionally, it appears that the bacteria may exhibit some unique differences in their immunogenicity as detected by the nonhuman primate and may contribute to the ability of the immune responses to effectively interact with these pathogens.

Role for the S-layer of Campylobacter rectus ATCC33238 in complement mediated killing and phagocytic killing by leukocytes from guinea pig and human peripheral blood

OBJECTIVE

The role of the S-layer of Campylobacter rectus ATCC 33238 in complement-mediated killing and interaction with leukocytes of the intraperitoneal cavity from guinea pigs and human peripheral blood was studied in vitro.

MATERIALS AND METHODS

Rabbit polyclonal anti-serum to whole C. rectus cells, a monoclonal antibody which recognizes 150 KDa S-layer protein antigen and a monoclonal antibody against lipopolysaccharide (LPS) were prepared. Sensitivities of C. rectus cells against complement mediated killing and phagocytic killing by peritoneal leukocytes of guinea pig and human peripheral leukocytes were examined in the presence or absence of a specific antibody.

RESULTS

C. rectus ATCC 33238 cells were moderately sensitive to complement mediated killing in the presence of rabbit polyclonal antibody against whole cells, and slightly sensitive in the presence of monoclonal antibody against S-layer. Ingestion and phagocytic killing of C. rectus cells by leukocytes were enhanced by the rabbit anti-serum and monoclonal antibody against S-layer, but not by the monoclonal antibody against LPS, pre-immune rabbit serum or control ascites. Viability of leukocytes was dependent on the number of ingested C. rectus cells.

CONCLUSIONS

The present study demonstrates that S-layer possessing C. rectus cells are resistant to complement mediated killing and phagocytic killing by leukocytes in the absence of specific antibody.

Motor nerve terminal degeneration provides a potential mechanism for rapid recovery in acute motor axonal neuropathy after Campylobacter infection

We investigated the possible mechanisms of paralysis and recovery in a patient with the acute motor axonal neuropathy (AMAN) pattern of the Guillain-Barré syndrome. The AMAN pattern of GBS is characterized clinically by acute paralysis without sensory involvement and electrodiagnostically by low compound motor action potential amplitudes, suggesting axonal damage, without evidence of demyelination. Many AMAN patients have serologic or culture evidence of recent Campylobacter jejuni infection. Pathologically, the most severe cases are characterized by wallerian-like degeneration of motor axons affecting the ventral roots as well as peripheral nerves, but some fatal cases have only minor changes in the roots and peripheral nerves, and some paralyzed patients with the characteristic electrodiagnostic findings of AMAN recover rapidly. The mechanism of paralysis and recovery in such cases has been uncertain. A 64-year-old woman with culture-proven Campylobacter upsaliensis diarrhea developed typical features of AMAN. She improved quickly following plasmapheresis. Her serum contained IgG anti-GM1 antibodies. The lipopolysaccharide of the organism bound peanut agglutinin. This binding was blocked by cholera toxin, suggesting that the organism contained the Gal(beta1-3)GalNAc epitope of GM1 in its lipopolysaccharide. Motor-point biopsy showed denervated neuromuscular junctions and reduced fiber numbers in intramuscular nerves. In contrast, the sural nerve biopsy was normal and skin biopsy showed normal dermal and epidermal innervation. In AMAN the paralysis may reflect degeneration of motor nerve terminals and intramuscular axons. In addition, the anti-GM1 antibodies, which can bind at nodes of Ranvier, might produce failure of conduction. These processes are potentially reversible and likely to underlie the capacity for rapid recovery that characterizes some cases of AMAN.

Molecular biology in diagnosis and epidemiology of Helicobacter pylori: PCR for the detection and AP-PCR for characterization of patient isolates

Infection with Helicobacter pylori causes chronic active gastritis and has been associated with gastric and duodenal ulcer disease. In biopsy samples of 110 patients with clinical symptoms of active gastritis, H. pylori was detected by means of the polymerase chain reaction (PCR), using species-specific primers defining a 858 bp DNA fragment of H. pylori urease beta-subunit. Sensitivity and specificity of the PCR was compared with culture, histology and Warthin-Starry stain (WSs), detection of H. pylori urease antibodies in serum and urease testing with the Campylobacter-like organism (CLO) test. PCR yielded specific amplification products in 53 cases, whereas culture of the organisms was positive in a subset of 50 cases. Only direct detection in histological sections of biopsy specimens had a higher sensitivity, with 65 positive samples. In contrast, the CLO test was negative in eleven culture-positive and PCR-positive cases. Significant urease antibody titres were found in 39 patients with histologically confirmed diagnosis. These results placed the sensitivity of PCR between tat of the Warthin-Starry stain (WSs) and that of culture. Therefore, PCR can be proposed as a useful rapid and time-saving technique for the detection of H.pylori in gastritis. For epidemiological purposes, fingerprinting with arbitrarily chosen primers by AP-PCR was evaluated. Strain-specific patterns with up to 13 fragments were achieved with 10-nucleotide or longer primers (21-nt) with a G + C content > or = 55%. Thirty-five of 40 strains investigated by this method were distinguishable with a single primer. These results suggest a high level of DNA sequence diversity within this species with the possibility of confirming the clonality in consecutive isolates from a single individual. Alternatively, an increased in-vivo mutation rate could be responsible for DNA divergence, resulting in specific strains for each individual patient.