Presence Of Bacterial Antigens Research Articles

Pathology, virulence associated gene profiling, antimicrobial susceptibility and pathogenicity of untypeable capsular serotypes of Pasteurella multocida isolated from slaughtered pigs of India.

Pasteurella multocida is widely distributed in all pig-rearing countries, affecting the economic viability and profitability of pig production. The present research highlights the molecular characterization and pathology of untypeable capsular serotypes of P. multocida in slaughtered pigs from prominent pig-rearing states of India. The prevalence of Pasteurellosis was 27.17% by PM-PCR assay, while isolation rate was 7.62%. The microscopic lesions of bronchopneumonia, tonsillitis, and the presence of bacterial antigens in IHC confirmed P. multocida with pathologies. In capsular typing, the majority of the isolates were untypeable with prevalence of 52.15% and 43.58% in molecular and microbiological methods respectively. All the isolates showed the uniform distribution of virulence genes such as exbB, nanB, sodC, plpB, and oma87 (100%), while the variations were observed in ptfA, hasR, ptfA, pfhA, hsf-1, and plpE genes. The untypeable isolates showed higher prevalence of hsf-1 gene as compared to others. The untypeable serotypes showed a higher degree of resistance to ampicillin, amoxicillin, and penicillin antibiotics. The mouse pathogenicity testing of untypeable capsular isolates confirmed its pathogenic potential. The higher frequency of pathogenic untypeable isolates with antibiotic resistance profile might pose a serious threat to the pigs, and therefore, preventive measures should be adopted for effective control.

A novel drug combination strategy that redesigns the pharmacological management of oral cancer.

e18053 Background: Biofilm formation is a continuous process in oral cancer patients, despite proper extirpation/elimination of a bacterial plaque via a surgical procedure or antibiotic treatment. Also, elimination of a bacterial plaque does not necessarily remove extant bacterial antigen-stimulated oral cancer cells. Therefore, combination drug treatment may be an appropriate approach to elucidate the confounding effects of bacterial antigens on anti-cancer drugs. Methods: Our drug combination strategy addressed both Gram-positive (Lipoteichoic acid [LTA]) and Gram-negative (Lipopolysaccharide [LPS]) bacterial antigens, to determine the effect of anti-cancer drugs on LPS/LTA/LPS+LTA-stimulated preclinical oral cancer models (SCC4, SCC9, SCC25, and Cal 27). The drug combination strategy was designed in six phases of treatment. In phase 1, plated cells were treated with different combinations of bacterial antigens in combination with anti-cancer drugs. In the phases 2 and 3, inhibitory drugs were introduced in the presence of bacterial antigens after 24 hours and 72 hours of bacterial antigen stimulation. In phases 4 and 5, inhibitory drugs were added after 24 hours and 72 hours of bacterial antigen stimulation. In phase 6, inhibitory drugs were applied in the absence of, and without stimulation with, bacterial antigens. Metabolic assays, reverse transcription quantitative PCR, Western blot, Proteome Profiler, apoptotic and ELISA assays were performed to validate the novel drug combination strategy. Results: Anti-cancer drug treatment on preclinical oral cancer models resulted in 43.6% ± 3.3% of precancerous models being apoptotic. To mimic pre-existing unhygenic conditions in oral cancer patients, prior stimulation of preclinical model with LPS+LTA 72 hours before drug treatment, reduced apoptosis to 32.2% ± 1.1% of cells. Apoptosis was almost annulled (2.98% ± 0.3%; p < 0.01) when drug treatment was carried out along with bacterial antigens. Treatment with drugs in the absence of bacterial antigens resulted in significantly more apoptotic cells than in presence of bacterial antigens (p < 0.0001). Metabolic and viability assay showed similar results like apoptotic assay. Conclusions: Bacterial antigens mimic the presence of Gram-negative and Gram-positive bacteria and thus severely affect the efficacy of anti-cancer drugs. The novel drug combination strategy redesigns the pharmacological management of oral squamous cell carcinoma.

ML218 HCl Is More Efficient Than Capsaicin in Inhibiting Bacterial Antigen-Induced Cal 27 Oral Cancer Cell Proliferation.

The bacterial antigen, lipopolysaccharide (LPS) and disruptions in calcium channels are independently known to influence oral cancer progression. Previously, we found that bacterial antigens, LPS and lipoteichoic acid (LTA) act as confounders during the action of capsaicin on Cal 27 oral cancer proliferation. As calcium channel drugs may affect oral cancer cell proliferation, we investigated the effect of ML218 HCl, a T-type voltage-gated calcium channel blocker, on the proliferation of Cal 27 oral cancer cells. We hypothesized that ML218 HCl could effectively reduce LPS-induced oral cancer cell proliferation. LPS and LTA antigens were added to Cal 27 oral cancer cells either prior to and/or concurrently with ML218 HCl treatment, and the efficacy of the treatment was evaluated by measuring Cal 27 proliferation, cell death and apoptosis. ML218 HCl inhibited oral cancer cell proliferation, increased apoptosis and cell death, but their efficacy was significantly reduced in the presence of bacterial antigens. ML218 HCl proved more effective than capsaicin in reducing bacterial antigen-induced Cal 27 oral cancer cell proliferation. Our results also suggest an interplay of proliferation factors during the bacterial antigens and calcium channel drug interaction in Cal 27. Bacterial antigen reduction of drug efficacy should be considered for developing newer pharmacological agents or testing the efficacy of the existing oral cancer chemotherapeutic agents. Finally, voltage gated calcium channel drugs should be considered for future oral cancer research.

Bacterial Antigens Reduced the Inhibition Effect of Capsaicin on Cal 27 Oral Cancer Cell Proliferation.

Oral cancer is a major global health problem with high incidence and low survival rates. The oral cavity contains biofilms as dental plaques that harbour both Gram-negative and Gram-positive bacterial antigens, lipopolysaccharide (LPS) and lipoteichoic acid (LTA), respectively. LPS and LTA are known to stimulate cancer cell growth, and the bioactive phytochemical capsaicin has been reported to reverse this effect. Here, we tested the efficacy of oral cancer chemotherapy treatment with capsaicin in the presence of LPS, LTA or the combination of both antigens. LPS and LTA were administered to Cal 27 oral cancer cells prior to and/or concurrently with capsaicin, and the treatment efficacy was evaluated by measuring cell proliferation and apoptotic cell death. We found that while capsaicin inhibits oral cancer cell proliferation and metabolism (MT Glo assay) and increases cell death (Trypan blue exclusion assay and Caspase 3/7 expression), its anti-cancer effect was significantly reduced on cells that are either primed or exposed to the bacterial antigens. Capsaicin treatment significantly increased oral cancer cells’ suppressor of cytokine signalling 3 gene expression. This increase was reversed in the presence of bacterial antigens during treatment. Our data establish a rationale for clinical consideration of bacterial antigens that may interfere with the treatment efficacy of oral cancer.

Bacterial outer membrane vesicles as a platform for biomedical applications: An update

Outer membrane vesicles (OMVs) are produced by Gram-negative bacteria both in vitro and in vivo. OMVs are nano-sized spherical vehicles formed by lipid bilayer membranes and contain multiple parent bacteria-derived components. Based on the presence of bacterial antigens, pathogen-associated molecular patterns (PAMPs), adhesins, various proteins and the vesicle structure, OMVs have been developed for biomedical applications as bacterial vaccines, adjuvants, cancer immunotherapy agents, drug delivery vehicles, and anti-bacteria adhesion agents. In this review, we analyze the contributions of the structure and composition of OMVs to their applications, summarize the methods used to isolate and characterize OMVs, and highlight recent progress and future perspectives of OMVs in biomedical applications.

Reaktive Arthritis

Reactive arthritis (ReA) was first described 100 years ago. It is defined as a sterile joint inflammation following a primary, extra-articular infection often in the form of urethritis or enteritis and less frequently respiratory infection and is characterized by the presence of bacterial antigens or non-culturable bacteria in the joint,. The prevalence is estimated to be 40/100,000 adults, while the incidence is 4-5/100,000. The classic HLA-B27-associated form with asymmetric involvement of the lower extremities and/or the spine is part of the spondyloarthritis concept. The phenomenon of persistence, which will be discussed in detail herein, plays an important role in the pathogenesis of ReA. Up to 30% of patients develop chronic symptoms posing a therapeutic challenge. Combination antibiotic treatment showing a response in up to 63% of patients has recently been proposed. Biologics could represent an alternative therapeutic option for patients showing a severe and highly active disease course.

Reactive arthritis

Reactive arthritis (ReA) has been recognized as a clinical disease entity for nearly 100 years. The prevalence is estimated to be 30-40/100,000 adults. The HLA-B27-associated form is part of the spondyloarthritis concept. According to the current hypothesis the arthritis follows a primary extra-articular infection and is characterized by the presence of bacterial antigen and/or of viable but non-culturable bacteria persisting within the joint. Pathogenesis involves the modification of host cells by pathogen-associated molecular patterns (PAMPs, e.g. lipopolysaccharide), bacterial effector proteins, the adaptive immune system, and the genetic background. Up to 30% of patients develop chronic symptoms, and therapeutic options for these patients are still limited. Data for recommendations to apply conventional disease-modifying anti-rheumatic drugs (DMARDs) are rare; however, sulfasalazine seems to be effective, and first reports on agents that block tumour necrosis factor (TNF) are promising. Combination therapy of several antibiotics might open the window to curing the disease; however, controlled clinical studies are needed.

Investigation of infectious agents associated with arthritis by reverse transcription PCR of bacterial rRNA

In reactive and postinfectious arthritis the joints are generally sterile but the presence of bacterial antigens and nucleic acids has been reported. To investigate whether organisms traffic to affected joints in these conditions, we performed reverse transcription PCR using universal primers to amplify any bacterial 16S rRNA sequences present in synovial fluid. Bacterial sequences were detected in most cases, even after treatment of the synovial fluid with DNase, implying the presence of bacterial RNA and therefore of transcriptionally active bacteria. Analysis of a large number of sequences revealed that, as reported in rheumatoid arthritis, most were derived from gut and skin commensals. Organisms known to have triggered arthritis in each case were not found by sequencing the products obtained using universal primers, but could in some cases be shown to be present by amplifying with species specific primers. This was the case for Yersinia pseudotuberculosis and Chlamydia trachomatis. However, in arthritis thought to be related to Campylobacter infection the sequences obtained were not from Campylobacter jejuni or C. coli, but from other Campylobacter spp. that are not known to be associated with reactive arthritis and are probably present as commensals in the gut. We conclude that although rRNA from reactive arthritis associated organisms can be detected in affected joints, bacterial RNA from many other bacteria is also present, as was previously noted in studies of other forms of inflammatory arthropathy.

Systemic reactivation of otitis media with effusion in a rat model

Objective: This study addresses the interaction of bacterial antigens, specifically peptidoglycan-polysaccharide (PG-PS) and lipopolysaccharide (LPS), in the induction and reactivation of mucoid middle ear effusions. Methods: Twenty-seven rats underwent eustachian tube obstruction before inoculation of the middle ear bulla with PG-PS. Three weeks later, after resolution of all middle ear effusions, 6 rats were randomly selected and euthanized as the first control group (control I). The remaining 21 animals were randomly assigned to 3 groups that received intravenous injections of Krebs Ringer (control II), PG-PS, and LPS, respectively. These rats were euthanized 2 days after intravenous injection. Middle ear mucin production and histologic changes were measured in all animals. Results: The mean concentrations of mucin were 0.94 ± 0.52 mg/mL, 0.41 ± 0.87 mg/mL, 16.33 ± 3.67 mg/mL, and 1.15 ± 0.41 mg/mL in the control I, control II, PG-PS, and LPS groups, respectively. Thus the mean concentration of mucin in the middle ear lavage samples was significantly greater in rats that were injected intravenously with PG-PS than in rats in other groups ( P < 0.05). Histologic analyses demonstrated a greater degree of goblet cell hyperplasia in the PG-PS group than in other groups. Conclusions: This is the first animal model of recurring otitis media with effusion in which a systemic injection of PG-PS was used to reactivate a middle ear effusion in rats previously primed with a transtympanic injection of PG-PS. This study suggests that after otitis media with effusion has resolved, it may be reactivated by the presence of bacterial antigens and/or cytokines in the systemic circulation. (Otolaryngol Head Neck Surg 1999;121:7-12.)

Staphylococcal enterotoxin B primes cytokine secretion and lytic activity in response to native bacterial antigens.

Superantigens stimulate T-lymphocyte proliferation and cytokine production, but the effects of superantigen exposure on cell function within a complex, highly regulated immune response remain to be determined. In this study, we demonstrate that superantigen exposure significantly alters the murine host response to bacterial antigens in an in vitro coculture system. Two days after exposure to the superantigen staphylococcal enterotoxin B, splenocytes cultured with Streptococcus mutans produced significantly greater amounts of gamma interferon (IFN-gamma) and interleukin-12 than did sham-injected controls. The majority of IFN-gamma production appeared to be CD8(+) T-cell derived since depletion of this cell type dramatically reduced the levels of IFN-gamma. To study host cell damage that may occur following superantigen exposure, we analyzed cytotoxicity to "bystander" fibroblast cells cultured with splenocytes in the presence of bacterial antigens. Prior host exposure to staphylococcal enterotoxin B significantly enhanced fibroblast cytotoxicity in the presence of bacteria. Neutralization of IFN-gamma decreased the amount of cytotoxicity observed. However, a greater reduction was evident when splenocyte-bacterium cocultures were separated from the bystander cell monolayer via a permeable membrane support. Increased cytotoxicity appears to be primarily dependent upon cell-cell contact. Collectively, these data indicate that overproduction of inflammatory cytokines may alter the activity of cytotoxic immune cells. Superantigen exposure exacerbates cytokine production and lytic cell activity when immune cells encounter bacteria in vitro and comparable activities could possibly occur in vivo.

T-cell response during Rhodococcus equi infection in a murine experimental model

Rhodococcus equi is a facultative intracellular bacterium that can cause pneumonia in both young horses and immunocompromised humans. In this study, we have tried to determine the T-cell populations that recognize this pathogen during murine infection, as well as the bacterial antigens recognized by these cells. When BALB/c mice were hyperimmunized with a virulent R. equi strain, we did not observe preferential expansion of a particular T-cell subset in their spleens. However, when the splenic T lymphocytes of the hyperimmunized BALB/c mice were cultured in the presence of killed bacteria, we found that alpha/beta CD4+ T cells proliferated and exhibited increased levels of the interleukin-2 receptor (IL2R). In order to ensure antigen specificity, two different controls were included in these experiments: (i) T-cell proliferation and expression of the IL2R in the presence of the major membrane constituent of Bacillus megaterium were studied comparatively with the presence of the R. equi bacterial antigen, and (ii) T-cell proliferation and expression of the IL2R from naive, non-infected mice in the presence of bacterial antigens were compared to those observed in hyperimmunized mice. In our study, the T cells from hyperimmunized mice did not significantly proliferate nor were they activated in the presence of non-related bacterial antigens, and T cells from naive mice were not found to significantly recognize R. equi antigens. When we studied the localization of R. equi antigens that could stimulate the in vitro proliferation and activation of T cells, we found that they were constituents of the bacterial cell wall and the cytoplasm, but they were not excreted in the culture medium. For these experiments, T-cell recognition of the bacterial antigens in hyperimmunized mice was compared to that of naive mice. With T-cell immunoblotting, we found that T-cell proliferation and activation were obtained with proteins having molecular masses of approximately 65, 43, 30, 22-27 and 15-17 kDa. It is noteworthy that among the recognized bacterial antigens, some have been described as being associated with virulence.

Recognition of chlamydial antigen by HLA-B27-restricted cytotoxic T cells in HLA-B*2705 transgenic CBA (H-2k) mice.

The association of reactive arthritis (ReA) with HLA-B27 and the presence of bacterial antigen in joints with ReA suggest that bacterial peptides might be presented by the HLA-B27 molecule and thus stimulate CD8 T cells. This study was performed to investigate the B27-restricted cytotoxic T lymphocyte (CTL) response to Chlamydia trachomatis, using the model of HLA-B27 transgenic mice. CBA (H-2k) mice homozygous for HLA-B*2705 and human beta2-microglobulin expression were immunized with C trachomatis or with the chlamydial 57-kd heat-shock protein (hsp57) coupled to latex beads. Cytotoxicity of lymphocytes from in vivo-primed transgenic mice was tested against C trachomatis-infected targets. Blocking experiments were performed with monoclonal antibodies (MAb) against class I major histocompatibility complex molecules. A Chlamydia-specific lysis of both B27-transfected and nontransfected target cells was observed. This response could be inhibited by anti-B27 and anti-H2 MAb. CTL from mice immunized with hsp57 were not able to lyse Chlamydia-infected target cells, and Chlamydia-specific CTL could not destroy targets loaded with hsp57. These results suggest the existence of at least 2 CTL populations in this mouse model: one recognizing peptide of bacteria-infected cells restricted by HLA-B*2705 and the other recognizing peptide of bacteria-infected cells restricted by the murine H-2Kk molecule. It does not appear that hsp57 is a major target for the CD8 T cell response directed against Chlamydia. This animal model opens the way for identifying bacterial epitopes presented by HLA-B27, and might thus help to clarify the pathogenesis of B27-associated diseases.

Etiology of Acute Lower Respiratory lhlct Infection in Children from Alabang, Metro Manila

The etiology of acute lower respiratory tract infection (ALRI) was identified in 235 (43.8%) of 537 hospitalized children less than 5 years of age. Clinical evidence of measles was found in 258 (48.0%) patients, of whom 59 had a second viral infection. A viral agent was identified in an additional 121 patients, so that a total of 379 (70.6%) had viral infections. After measles, respiratory syncytial virus was the most common respiratory virus. Bacteremia was noted in 72 children (13.4%), occurring as frequently in children with measles (14.8%) as in those without (12.1%); Haemophilus influenzae and Salmonella typhi were predominant in the former, and H. influenzae, Staphylococcus aureus, and Streptococcus pneumoniae were prominent in the latter. The presence of bacterial antigen in urine was not helpful in identifying bacterial infection. Extrapulmonary and intrapleural complications, concomitant measles, complicated ALRI, female gender, and malnutrition were associated with increased mortality among children with ALRI. The importance of measles immunization, vitamin A supplementation for alleviation of defects associated with malnutrition, and timely antimicrobial therapy is emphasized.

Detection of Bacterial Antigens in Body Fluids by the Phadebact System

150 infected patients from 2 study centers had body fluids examined for presence of bacterial antigens (group B streptococcus, Streptococcus pneumoniae, Neisseria meningitidis and Haemophilus influenzae type b) using the Pharmacia Phadebact system. The rates of detection of the pneumococcal antigens in the urine or serum of the patients with pneumococcal pneumonia, pneumococcal bacteremia and pneumococcal meningitis were 0.38, 0.47 and 0.5, respectively. The overall detection rate for H. influenzae infections was 0.92 and for group B streptococcal infections 0.87. Serum and urine from 100 non-infected patients were also tested for the presence of group B streptococcus, S. pneumoniae, N. meningitidis and H. influenzae type b antigens with only 1 false positive (H. influenzae type b).

Failure of Diagnosing Group B Meningococcal Meningitis by Immunoelectroosmophoresis

AbstractThe immunoelectroosmophoresis (IEOP) technique has been used to show the presence of bacterial antigens in the cerebrospinal fluid (CSF) of 28 cases of group B meningococcal meningitis. No specific precipitation was observed with any of the 28 CSF examined. Up until now this method has been of no value in the diagnosis of group B meningococcal meningitis.

A study of the antigenicity of T3 and T4 coli-dysentery bacteriophages during the vegetative stage of development.

The development of viral neutralizing antibodies in animals injected with T(3) or T(4) phage is considerably inhibited by the presence of bacterial antigens. A new procedure has been described to liberate phage from infected E. coli B bacteria by inducing lysis with penicillin. By immunological means it has been shown that T(4)-infected cultures of E. coli B, in which phage development has been inhibited with proflavine, contain the viral neutralizing antigen after lysis. In contrast, it has not been possible to demonstrate by immunological means the appearance of viral neutralizing antigen in E. coli B infected with T(3) prior to the appearance of intracellular phage.