Displaying publications 1 - 20 of 37 in total

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  1. Puthucheary SD, Anuar AS, Tee TS
    PMID: 20578523
    An immunofluorescent assay (IFAT) using whole cell antigen derived from Burkholderia thailandensis used for detection of total antibodies to Burkholderia pseudomallei, was found to compare favorably with a previous published report on a B. pseudomallei IFAT assay. At a 1:20 cut-off titer, the assay had high sensitivity (98.9%) and satisfactory specificity (92.3%), when tested against sera from 94 patients suspected of melioidosis. Sera from 12 patients with culture proven melioidosis gave absolute concordance with the 2 test antigens. No sera from 50 blood donors had a titer of > or =20. Cross-reactivity with patients' sera positive for Chlamydia, Mycoplasma, Legionella and typhoid was not observed, except for 3 sera from typhus patients and one from a patient with leptospirosis. The major advantage of this assay is that the cultivation and preparation of B. thailandensis as antigen can be carried out in any laboratory with basic microbiological set-up. The serodiagnosis of melioidosis can be made safe for medical laboratory personnel, particularly in B. pseudomallei endemic regions.
    Matched MeSH terms: Antibodies, Bacterial/immunology*
  2. Naidu BR, Ngeow YF, Pang T
    Eur J Epidemiol, 2003;18(2):135-7.
    PMID: 12733835
    Chlamydophila pneumoniae, an important respiratory pathogen causing lower respiratory tract infections, has also been implicated in coronary heart disease (CHD). This study reports a cross-sectional, demographic, serological analysis of the prevalence of Chlamydophila pneumoniae antibodies in a multiracial Malaysian population. Generally, Malaysian Indians had the highest degree of seropositivity (58%) followed by the Chinese (54%) and the Malays (32%), results which were statistically significant (CI: 95%; p < 0.01). Interestingly, this trend was also reflected in the study group consisting of patients with acute myocardial infarctions (AMI) and chronic CHD. Again, the Indians were more frequently seropositive (65%), with more than 50% having IgG titres > or = 128. Comparatively, the Chinese and Malays showed 51 and 17% seropositivity respectively. These results were also statistically significant (CI: 95%; p < 0.01). Malaysian Indians are more commonly afflicted with CHD. A variety of factors have been suggested to explain this prevalence including diet, social habits, genetics and the possible role of infectious agents. This study notes an interesting association between this pattern of racial prevalence and the possible role of C. pneumoniae infections as a contributory/predisposing factor in the development of cardiovascular disease.
    Matched MeSH terms: Antibodies, Bacterial/immunology*
  3. Xian TH, Sinniah K, Yean CY, Krishnamoorthy V, Bahari MB, Ravichandran M, et al.
    BMC Immunol, 2020 05 25;21(1):29.
    PMID: 32450807 DOI: 10.1186/s12865-020-00360-1
    BACKGROUND: Cholera, an acute watery diarrhoeal disease caused by Vibrio cholerae serogroup O1 and O139 across the continents. Replacing the existing WHO licensed killed multiple-dose oral cholera vaccines that demand 'cold chain supply' at 2-8 °C with a live, single-dose and cold chain-free vaccine would relieve the significant bottlenecks and cost determinants in cholera vaccination campaigns. In this direction, a prototype cold chain-free live attenuated cholera vaccine formulation (LACV) was developed against the toxigenic wild-type (WT) V. cholerae O139 serogroup. LACV was found stable and retained its viability (5 × 106 CFU/mL), purity and potency at room temperature (25 °C ± 2 °C, and 60% ± 5% relative humidity) for 140 days in contrast to all the existing WHO licensed cold-chain supply (2-8 °C) dependent killed oral cholera vaccines.

    RESULTS: The LACV was evaluated for its colonization potential, reactogenicity, immunogenicity and protective efficacy in animal models after its storage at room temperature for 140 days. In suckling mice colonization assay, the LACV recorded the highest recovery of (7.2 × 107 CFU/mL) compared to those of unformulated VCUSM14P (5.6 × 107 CFU/mL) and the WT O139 strain (3.5 × 107 CFU/mL). The LACV showed no reactogenicity even at an inoculation dose of 104-106 CFU/mL in a rabbit ileal loop model. The rabbits vaccinated with the LACV or unformulated VCUSM14P survived a challenge with WT O139 and showed no signs of diarrhoea or death in the reversible intestinal tie adult rabbit diarrhoea (RITARD) model. Vaccinated rabbits recorded a 275-fold increase in anti-CT IgG and a 15-fold increase in anti-CT IgA antibodies compared to those of rabbits vaccinated with unformulated VCUSM14P. Vibriocidal antibodies were increased by 31-fold with the LACV and 14-fold with unformulated VCUSM14P.

    CONCLUSION: The vaccine formulation mimics a natural infection, is non-reactogenic and highly immunogenic in vivo and protects animals from lethal wild-type V. cholerae O139 challenge. The single dose LACV formulation was found to be stable at room temperature (25 ± 2 °C) for 140 days and it would result in significant cost savings during mass cholera vaccination campaigns.

    Matched MeSH terms: Antibodies, Bacterial/immunology
  4. Law CT, Camacho F, Garcia-Alles LF, Gilleron M, Sarmiento ME, Norazmi MN, et al.
    Tuberculosis (Edinb), 2019 01;114:9-16.
    PMID: 30711162 DOI: 10.1016/j.tube.2018.11.002
    Tuberculosis (TB) is the main cause of mortality among all infectious diseases. The presentation of lipids by CD1b molecules and the interactions of the CD1b-lipid complexes with the immune receptors are important for the understanding of the immune response to Mycobacterium tuberculosis (Mtb), and to develop TB control methods. A specific domain antibody (dAbk11) recognizing the complex of CD1b with Mtb sulphoglycolipid (Ac2SGL) had been previously developed. In order to study the interactions of dAbk11 with Ac2SGL:CD1b, the conformation of Ac2SGL within CD1b was first modelled. The orientation of dAbκ11 with Ac2SGL:CD1b was then predicted by a docking experiment and the complex was sampled using molecular dynamics simulation. Data showed that dAbκ11 Tyr32 OH plays a decisive role in interacting with Ac2SGL alkyl tail HO17. The binding free energy calculation showed that Ac2SGL establish strong hydrophobic interactions with dAbκ11. The model also predicted a higher affinity for the natural sulfoglycolipid (Ac2SGL) than the synthetic analogue (SGL12), which was supported by the ELISA data. These results shed light on the likely mechanism of interactions between Ac2SGL:CD1b and dAbκ11, thus making possible to envision the strategies for dAbκ11 optimization for possible future applications.
    Matched MeSH terms: Antibodies, Bacterial/immunology
  5. Hamidon NH, Suraiya S, Sarmiento ME, Acosta A, Norazmi MN, Lim TS
    Appl Biochem Biotechnol, 2018 Mar;184(3):852-868.
    PMID: 28884285 DOI: 10.1007/s12010-017-2582-5
    B cells and in particular antibodies has always played second fiddle to cellular immunity in regard to tuberculosis (TB). However, recent studies has helped position humoral immunity especially antibodies back into the foray in relation to TB immunity. Therefore, the ability to correlate the natural antibody responses of infected individuals toward TB antigens would help strengthen this concept. Phage display is an intriguing approach that can be utilized to study antibody-mediated responses against a particular infection via harvesting the B cell repertoire from infected individuals. The development of disease-specific antibody libraries or immune libraries is useful to better understand antibody-mediated immune responses against specific disease antigens. This study describes the generation of an immune single-chain variable fragment (scFv) library derived from TB-infected individuals. The immune library with an estimated diversity of 109 independent clones was then applied for the identification of monoclonal antibodies against Mycobacterium tuberculosis α-crystalline as a model antigen. Biopanning of the library isolated three monoclonal antibodies with unique gene usage. This strengthens the role of antibodies in TB immunity in addition to the role played by cellular immunity. The developed library can be applied against other TB antigens and aid antibody-derived TB immunity studies in the future.
    Matched MeSH terms: Antibodies, Bacterial/immunology*
  6. Naidu BR, Ngeow YF, Wang LF, Chan L, Yao ZJ, Pang T
    Immunol Lett, 1998 Jun;62(2):111-5.
    PMID: 9698107
    Random 15-mer peptides displayed on filamentous phages were screened in binding studies using a Chlamydia pneumoniae-specific monoclonal antibody (RR-402) and affinity-purified, polyclonal sera from patients seropositive for C. pneumoniae infections by the microimmunofluorescence (MIF) test. One 15-mer epitope, epitope Cpnl5A (LASLCNPKPSDAPVT) was identified in both the monoclonal and polyclonal screenings, and showed higher ELISA reactivity with C. pneumoniae MIF-positive sera compared to patients with other chlamydial infections, non-chlamydial respiratory infections and normal healthy sera (MIF-negative). Interestingly, epitope Cpnl5A also showed significant (52%) amino acid sequence homology to the 56 kDa type-specific antigen of Rickettsia tsutsugamushi, a protein implicated in the virulence of this organism.
    Matched MeSH terms: Antibodies, Bacterial/immunology*
  7. Camacho F, Sarmiento ME, Reyes F, Kim L, Huggett J, Lepore M, et al.
    Int J Mycobacteriol, 2016 06;5(2):120-7.
    PMID: 27242221 DOI: 10.1016/j.ijmyco.2015.12.002
    OBJECTIVE/BACKGROUND: The development of new tools capable of targeting Mycobacterium tuberculosis (Mtb)-infected cells have potential applications in diagnosis, treatment, and prevention of tuberculosis. In Mtb-infected cells, CD1b molecules present Mtb lipids to the immune system (Mtb lipid-CD1b complexes). Because of the lack of CD1b polymorphism, specific Mtb lipid-CD1b complexes could be considered as universal Mtb infection markers. 2-Stearoyl-3-hydroxyphthioceranoyl-2'-sulfate-α-α'-d-trehalose (Ac2SGL) is specific for Mtb, and is not present in other mycobacterial species. The CD1b-Ac2SGL complexes are expressed on the surface of human cells infected with Mtb. The aim of this study was to generate ligands capable of binding these CD1b-Ac2SGL complexes.

    METHODS: A synthetic human scFv phage antibody library was used to select phage-displayed antibody fragments that recognized CD1b-Ac2SGL using CD1b-transfected THP-1 cells loaded with Ac2SGL.

    RESULTS: One clone, D11-a single, light-variable domain (kappa) antibody (dAbκ11)-showed high relative binding to the Ac2SGL-CD1b complex.

    CONCLUSION: A ligand recognizing the Ac2SGL-CD1b complex was obtained, which is a potential candidate to be further tested for diagnostic and therapeutic applications.

    Matched MeSH terms: Antibodies, Bacterial/immunology*
  8. Radhakrishnan AK, Mahalingam D, Selvaduray KR, Nesaretnam K
    Biomed Res Int, 2013;2013:782067.
    PMID: 23936847 DOI: 10.1155/2013/782067
    This study compared the ability of three forms of vitamin E [tocotrienol-rich fraction (TRF), alpha-tocopherol (α-T), and delta-tocotrienol (δ-T3)] to enhance immune response to tetanus toxoid (TT) immunisation in a mouse model. Twenty BALB/c mice were divided into four groups of five mice each. The mice were fed with the different forms of vitamin E (1 mg) or vehicle daily for two weeks before they were given the TT vaccine [4 Lf] intramuscularly (i.m.). Booster vaccinations were given on days 28 and 42. Serum was collected (days 0, 28, and 56) to quantify anti-TT levels. At autopsy, splenocytes harvested were cultured with TT or mitogens. The production of anti-TT antibodies was augmented (P < 0.05) in mice that were fed with δ-T3 or TRF compared to controls. The production of IFN-γ and IL-4 by splenocytes from the vitamin E treated mice was significantly (P < 0.05) higher than that from controls. The IFN-γ production was the highest in animals supplemented with δ-T3 followed by TRF and finally α-T. Production of TNF-α was suppressed in the vitamin E treated group compared to vehicle-supplemented controls. Supplementation with δ-T3 or TRF can enhance immune response to TT immunisation and production of cytokines that promote cell-mediated (TH1) immune response.
    Matched MeSH terms: Antibodies, Bacterial/immunology*
  9. Sasidharan S, Uyub AM
    J Immunoassay Immunochem, 2009;30(1):70-81.
    PMID: 19117203 DOI: 10.1080/15321810802569477
    Helicobacter pylori is recognized as a major case of gastritis and peptic ulcer and a key factor in the development of gastric cancer, gastric lymphoma, and non-ulcerative dyspepsia in man. The detection of antibodies specific for strains of H. pylori has demonstrated the value of serology for providing evidence of infection. The present study was conducted to detect the antigenic proteins of excretory antigen of H. pylori with Western blotting and examine whether anti-H. pylori IgG and IgA antibodies from H. pylori positive patients cross-react with antigens from other common bacterial pathogens. By using SDS-PAGE, 20 different proteins were found in the excretory antigen. By Western blotting and absorption studies, there were indications that anti-H. pylori IgA antibodies directed against 54 kDa, 50 kDa and 27 kDa cross-reacted with antigens from other bacteria, and that H. pylori proteins of 99 kDa, 88 kDa and 81 kDa possibly shared similar epitope with antigens of other pathogens not tested in the absorption studies. The cross-reactivity occurred in this study was not significantly affect the performance of the in-house ELISA.
    Matched MeSH terms: Antibodies, Bacterial/immunology*
  10. Chan SW, Nathan S
    FEMS Immunol. Med. Microbiol., 2005 Jan 1;43(1):37-44.
    PMID: 15607634
    Filamentous phage random peptide libraries were used to identify the epitopes of Burkholderia pseudomallei protease by panning against IgG polyclonal sera that exhibited protease neutralizing properties. The isolated fusion peptides presented a consensus peptide sequence, TKSMALSG, which closely resembles part of the active site sequence, 435GTSMATPHVAG445, of B. pseudomallei serine metalloprotease. By comparing the consensus sequence, TKSMALSG, with the predicted three-dimensional molecular model of B. pseudomallei serine metalloprotease, it appears that the potential antibody binding epitope was buried within the molecule. This active site was conformational whereby one continuous sub-region (SMA) was located between two discontinuous sub-regions, supplied by the flanking residues in the same polypeptide. All phages selected from the biopanning with IgG polyclonal sera showed good binding towards the polyclonal antibodies when compared to the negative control. In addition, these peptide-bearing phages showed competitive inhibition of B. pseudomallei serine metalloprotease binding to the polyclonal IgG.
    Matched MeSH terms: Antibodies, Bacterial/immunology
  11. Rohani MY, Hasnidah D, Ong KH
    Malays J Pathol, 1998 Jun;20(1):31-3.
    PMID: 10879261
    A chromatographic immunoassay cholera antigen detection kit, the Cholera Spot test, was evaluated. The test was found to be specific with a sensitivity of 10(6) cfu/ml for the direct detection of V. cholerae in simulated stool specimens and 10 cfu/ml in simulated cotton-tipped swab specimens after overnight incubation in alkaline peptone water. This enables early recognition of cholera cases and their contacts so that prevention and control measures can be promptly instituted.
    Matched MeSH terms: Antibodies, Bacterial/immunology
  12. Dass SA, Norazmi MN, Acosta A, Sarmiento ME, Tye GJ
    Int J Biol Macromol, 2020 Jul 15;155:305-314.
    PMID: 32240734 DOI: 10.1016/j.ijbiomac.2020.03.229
    T cell receptor (TCR)-like antibodies, obtained with the use of phage display technology, sandwich the best of the both arms of the adaptive immune system. In this study, in vitro selections against the latency associated Mycobacterium tuberculosis (Mtb) heat shock protein 16 kDa antigen (16 kDa) presented by HLA-A*011 and HLA-A*24 were carried out with the use of a human domain phage antibody library. TCR-like domain antibodies (A11Ab and A24Ab) were successfully generated recognizing 16 kDa epitopes presented by HLA-A*011 and HLA-A*24 molecules respectively. Both antibodies were found to be functional in soluble form and exhibited strong binding capacity against its targets. The results obtained support the future evaluation of these ligands for the development of diagnostic and therapeutic tools for tuberculosis infection.
    Matched MeSH terms: Antibodies, Bacterial/immunology*
  13. Awaludin N, Abdullah J, Salam F, Ramachandran K, Yusof NA, Wasoh H
    Anal Biochem, 2020 12 01;610:113876.
    PMID: 32750357 DOI: 10.1016/j.ab.2020.113876
    The identification of rice bacterial leaf blight disease requires a simple, rapid, highly sensitive, and quantitative approach that can be applied as an early detection monitoring tool in rice health. This paper highlights the development of a turn-off fluorescence-based immunoassay for the early detection of Xanthomonas oryzae pv. oryzae (Xoo), a gram-negative bacterium that causes rice bacterial leaf blight disease. Antibodies against Xoo bacterial cells were produced as specific bio-recognition molecules and the conjugation of these antibodies with graphene quantum dots and gold nanoparticles was performed and characterized, respectively. The combination of both these bio-probes as a fluorescent donor and metal quencher led to changes in the fluorescence signal. The immunoreaction between AntiXoo-GQDs, Xoo cells, and AntiXoo-AuNPs in the immuno-aggregation complex led to the energy transfer in the turn-off fluorescence-based quenching system. The change in fluorescence intensity was proportional to the logarithm of Xoo cells in the range of 100-105 CFU mL-1. The limit of detection was achieved at 22 CFU mL-1 and the specificity test against other plant disease pathogens showed high specificity towards Xoo. The detection of Xoo in real plant samples was also performed in this study and demonstrated satisfactory results.
    Matched MeSH terms: Antibodies, Bacterial/immunology
  14. Lachumanan R, Devi S, Cheong YM, Rodda SJ, Pang T
    Infect Immun, 1993 Oct;61(10):4527-31.
    PMID: 7691753
    Binding studies of 160 overlapping, synthetic octapeptides from the hydrophilic regions of the Sta58 major outer membrane protein of Rickettsia tsutsugamushi with sera from patients with scrub typhus revealed 15 immunodominant peptides which are recognized by all the sera tested. Further analysis of the specificity of peptide binding with five of these peptides indicated that the peptides showed significantly stronger binding to scrub typhus patients' sera than they did to sera from patients with other febrile illnesses common in the region, i.e., malaria, dengue fever, typhoid fever, and leptospirosis. The main antibody class binding to these peptides appears to be immunoglobulin M, and there appears to be little correlation between reactivity with peptides and antibody titers measured by the indirect immunoperoxidase test.
    Matched MeSH terms: Antibodies, Bacterial/immunology
  15. Harikrishnan H, Banga Singh KK, Ismail A
    PLoS One, 2017;12(8):e0182878.
    PMID: 28846684 DOI: 10.1371/journal.pone.0182878
    Bacillary dysentery caused by infection with Shigella spp. remains as serious and common health problem throughout the world. It is a highly multi drug resistant organism and rarely identified from the patient at the early stage of infection. S. sonnei is the most frequently isolated species causing shigellosis in industrialized countries. The antigenicity of outer membrane protein of this pathogen expressed during human infection has not been identified to date. We have studied the antigenic outer membrane proteins expressed by S. sonnei, with the aim of identifying presence of specific IgA and IgG in human serum against the candidate protein biomarkers. Three antigenic OMPs sized 33.3, 43.8 and 100.3 kDa were uniquely recognized by IgA and IgG from patients with S. sonnei infection, and did not cross-react with sera from patients with other types of infection. The antigenic proteome data generated in this study are a first for OMPs of S. sonnei, and they provide important insights of human immune responses. Furthermore, numerous prime candidate proteins were identified which will aid the development of new diagnostic tools for the detection of S. sonnei.
    Matched MeSH terms: Antibodies, Bacterial/immunology*
  16. Panchanathan V, Naidu BR, Devi S, Di Pasquale A, Mason T, Pang T
    Immunol Lett, 1998 Jun;62(2):105-9.
    PMID: 9698106
    A series of 122, 9-mer overlapping peptides based on the sequence of the Salmonella typhi GroEL gene was synthesized on the surfaces of polyethylene pins and screened with monoclonal antibody to GroEL and with human sera from patients with typhoid fever and normal healthy blood donors. Three immunogenic epitopes corresponding to peptides EGQDRGYSY, YSYNKETGE and GKGTEEKEK were identified upon screening with the human sera. In addition, screening of the peptides with a monoclonal antibody to GroEL detected binding to a third peptide, KGGKGTEEK, which contains a common overlapping sequence to peptide GKGTEEKEK. Identification and definition of these epitopes will be important in delineating the biological and immunological functions of this protein and in designing better diagnostic tests and vaccines.
    Matched MeSH terms: Antibodies, Bacterial/immunology
  17. Riazi M, Zainul FZ, Bahaman AR, Amran F, Khalilpour A
    Indian J Med Res, 2014 Feb;139(2):308-13.
    PMID: 24718408
    Leptospirosis is a widespread zoonotic disease and a public health problem, particularly in tropical and subtropical countries. Varied clinical manifestations of the disease frequently lead to misdiagnosis resulting in life-threatening multi-organ complications. Therefore, early laboratory investigation using an appropriate diagnostic approach is crucial. In the present study, a potential protein marker was identified and evaluated for its usefulness in the serodiagnosis of acute leptospirosis.
    Matched MeSH terms: Antibodies, Bacterial/immunology
  18. Lim FS, Koh MT, Tan KK, Chan PC, Chong CY, Shung Yehudi YW, et al.
    BMC Infect Dis, 2014;14:530.
    PMID: 25278086 DOI: 10.1186/1471-2334-14-530
    BACKGROUND: The immunogenicity, reactogenicity, and safety of the 10-valent pneumococcal non-typeable Haemophilus influenzae protein D conjugate vaccine (PHiD-CV) co-administered with routine childhood vaccines were evaluated among infants from Singapore and Malaysia, where PHiD-CV has been licensed.
    METHODS: In the primary vaccination phase, 298 infants from Singapore and 168 infants from Malaysia were randomised to receive the Phase III Clinical (Clin) or the Commercial (Com) lot of PHiD-CV at 2, 3, and 5 months of age. In the booster vaccination phase, 238 toddlers from Singapore received one dose of the PHiD-CV Commercial lot at 18-21 months of age. Immune responses to pneumococcal polysaccharides were measured using 22F-inhibition enzyme-linked immunosorbent assay (ELISA) and functional opsonophagocytic activity (OPA) assay and to protein D, using ELISA.
    RESULTS: Immune responses induced by primary vaccination with the PHiD-CV Commercial lot were non-inferior to the Phase III Clinical lot in terms of adjusted antibody geometric mean concentration (GMC) ratios for each vaccine pneumococcal serotype and protein D. For each vaccine pneumococcal serotype, ≥93.6% and ≥88.5% of infants from Malaysia and Singapore had post-primary vaccination antibody concentrations ≥0.2 μg/mL and OPA titres ≥8, in the Clin and Com groups, respectively. For each vaccine pneumococcal serotype, ≥60.8% and ≥98.2% of toddlers from Singapore had pre- and post-booster antibody concentrations ≥0.2 μg/mL, in the Clin and Com groups, respectively. All children, except one, had measurable anti-protein D antibodies and the primary and booster doses of the co-administered vaccines were immunogenic. The incidence of each grade 3 solicited symptom was ≤11.1% in both study phases. No serious adverse events considered causally related to vaccination were reported throughout the study.
    CONCLUSIONS: PHiD-CV given as three-dose primary vaccination to infants in Singapore and Malaysia and booster vaccination to toddlers in Singapore was shown to be immunogenic with a clinically acceptable-safety profile.This study has been registered at http://www.clinicaltrials.govNCT00808444 and NCT01119625.
    Matched MeSH terms: Antibodies, Bacterial/immunology
  19. Mariappan V, Vellasamy KM, Thimma JS, Hashim OH, Vadivelu J
    Vaccine, 2010 Feb 3;28(5):1318-24.
    PMID: 19944788 DOI: 10.1016/j.vaccine.2009.11.027
    Burkholderia cepacia is an opportunistic human pathogen associated with lung infections. Secretory proteins of B. cepacia are known to be involved in virulence and may mediate important host-pathogen interactions. In the present study, secretory proteins isolated from B. cepacia culture supernatant were separated using two-dimensional gel electrophoresis, followed by Western blot analysis to identify the immunogenic proteins. Mice antibodies raised to B. cepacia inactivated whole bacteria, outer membrane protein and culture filtrate antigen detected 74, 104 and 32 immunogenic proteins, respectively. Eighteen of these immunogenic proteins which reacted with all three antibodies were identified and might be potential molecules as a diagnostic marker or a putative candidate vaccine against B. cepacia infections.
    Matched MeSH terms: Antibodies, Bacterial/immunology
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