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Fulltext Helicobacter pylori recombinant UreG protein: cloning, expression, and assessment of its seroreactivity

Khalilpour A, Osman S, Yunus MH, Santhanam A, Vellasamy N, Noordin R

BMC Res Notes, 2014;7:809.
PMID: 25406411 DOI: 10.1186/1756-0500-7-809

Helicobacter pylori is a human pathogen and during the process of infection, antigens from the bacterium elicit strong host humoral immune responses. In our previous report, native H. pylori UreG protein showed good reactivity with sera from H. pylori patients. This study was aimed at producing the recombinant form of the protein (rUreG) and determining its seroreactivities.

Matched MeSH terms: Bacterial Proteins/immunology*
Antigenic proteins of Helicobacter pylori of potential diagnostic value

Khalilpour A, Santhanam A, Wei LC, Saadatnia G, Velusamy N, Osman S, et al.

Asian Pac J Cancer Prev, 2013;14(3):1635-42.
PMID: 23679248

Helicobacter pylori antigen was prepared from an isolate from a patient with a duodenal ulcer. Serum samples were obtained from culture-positive H. pylori infected patients with duodenal ulcers, gastric ulcers and gastritis (n=30). As controls, three kinds of sera without detectable H. pylori IgG antibodies were used: 30 from healthy individuals without history of gastric disorders, 30 from patients who were seen in the endoscopy clinic but were H. pylori culture negative and 30 from people with other diseases. OFF-GEL electrophoresis, SDS-PAGE and Western blots of individual serum samples were used to identify protein bands with good sensitivity and specificity when probed with the above sera and HRP-conjugated anti-human IgG. Four H. pylori protein bands showed good (≥ 70%) sensitivity and high specificity (98-100%) towards anti-Helicobacter IgG antibody in culture- positive patients sera and control sera, respectively. The identities of the antigenic proteins were elucidated by mass spectrometry. The relative molecular weights and the identities of the proteins, based on MALDI TOF/ TOF, were as follows: CagI (25 kDa), urease G accessory protein (25 kDa), UreB (63 kDa) and proline/pyrroline- 5-carboxylate dehydrogenase (118 KDa). These identified proteins, singly and/or in combinations, may be useful for diagnosis of H. pylori infection in patients.

Matched MeSH terms: Bacterial Proteins/immunology
Evaluation of bovine antibody responses to haemorrhagic septicaemia vaccine

Johnson RB, Dawkins HJ, Spencer TL, Saharee AA, Bahaman AR, Ramdani, et al.

Res Vet Sci, 1989 Sep;47(2):277-9.
PMID: 2508206

ELISA and immunoblotting techniques were used to examine the humoral immune response to Pasteurella multocida, in bovine sera from Indonesia and Malaysia. Elevated levels of antibody to a crude lipopolysaccharide preparation were found in vaccinated animals. In addition to the response to lipopolysaccharide, antibodies from the vaccinated cattle strongly labelled five to six of the 40 protein bands in this organism.

Matched MeSH terms: Bacterial Proteins/immunology
Fulltext Immunogenic recombinant Burkholderia pseudomallei MprA serine protease elicits protective immunity in mice

Chin CY, Tan SC, Nathan S

Front Cell Infect Microbiol, 2012;2:85.
PMID: 22919676 DOI: 10.3389/fcimb.2012.00085

Burkholderia pseudomallei is resistant to a diverse group of antimicrobials including third generation cephalosporins whilst quinolones and aminoglycosides have no reliable effect. As therapeutic options are limited, development of more effective forms of immunotherapy is vital to avoid a fatal outcome. In an earlier study, we reported on the B. pseudomallei serine MprA protease, which is relatively stable over a wide pH and temperature range and digests physiological proteins. The present study was carried out to evaluate the immunogenicity and protective efficacy of the MprA as a potential vaccine candidate. In BALB/c mice immunized with recombinant MprA protease (smBpF4), a significantly high IgG titer was detectable. Isotyping studies revealed that the smBpF4-specific antibodies produced were predominantly IgG(1), proposing that immunization with smBpF4 triggered a Th2 immune response. Mice were immunized with smBpF4 and subsequently challenged with B. pseudomallei via the intraperitoneal route. Whilst control mice succumbed to the infection by day 9, smBpF4-immunized mice were protected against the lethal challenge and survived beyond 25 days post-infection. In conclusion, MprA is immunogenic in melioidosis patients whilst also eliciting a strong immune response upon bacterial challenge in mice and presents itself as a potential vaccine candidate for the treatment of melioidosis.

Matched MeSH terms: Bacterial Proteins/immunology*
Fulltext In Silico identification of M. TB proteins with diagnostic potential

Calero R, Mirabal M, Bouza J, Guzmán MV, Carrillo H, López Y, et al.

BMC Immunol, 2013;14 Suppl 1:S9.
PMID: 23458073 DOI: 10.1186/1471-2172-14-S1-S9

TB, caused by Mycobacterium tuberculosis (MTB), is one of the major global infectious diseases. For the pandemic control, early diagnosis with sensitive and specific methods is fundamental. With the advent of bioinformatics' tools, the identification of several proteins involved in the pathogenesis of TB (TB) has been possible. In the present work, the MTB genome was explored to look for molecules with possible antigenic properties for their evaluation as part of new generation diagnostic kits based on the release of cytokines. Seven proteins from the MTB proteome and some of their combinations suited the computational test and the results suggested their potential use for the diagnosis of infection in the following population groups: Cuba, Mexico, Malaysia and sub-Saharan Africa. Our predictions were performed using public bioinformatics tools plus three computer programs, developed by our group, to facilitate information retrieval and processing.

Matched MeSH terms: Bacterial Proteins/immunology*
Fulltext Prospective evaluation of antibody response to Streptococcus gallolyticus and risk of colorectal cancer

Butt J, Jenab M, Willhauck-Fleckenstein M, Michel A, Pawlita M, Kyrø C, et al.

Int J Cancer, 2018 Jul 15;143(2):245-252.
PMID: 29377173 DOI: 10.1002/ijc.31283

The gut microbiome is increasingly implicated in colorectal cancer (CRC) development. A subgroup of patients diagnosed with CRC show high antibody responses to Streptococcus gallolyticus subspecies gallolyticus (SGG). However, it is unclear whether the association is also present pre-diagnostically. We assessed the association of antibody responses to SGG proteins in pre-diagnostic serum samples with CRC risk in a case-control study nested within a prospective cohort. Pre-diagnostic serum samples from 485 first incident CRC cases (mean time between blood draw and diagnosis 3.4 years) and 485 matched controls in the European Prospective Investigation into Nutrition and Cancer (EPIC) study were analyzed for antibody responses to 11 SGG proteins using multiplex serology. Odds ratios (OR) and 95% confidence intervals (CI) were estimated using multivariable conditional logistic regression models. Antibody positivity for any of the 11 SGG proteins was significantly associated with CRC risk with 56% positive controls compared to 63% positive cases (OR: 1.36, 95% CI: 1.04-1.77). Positivity for two or more proteins of a previously identified SGG 6-marker panel with greater CRC-specificity was also observed among 9% of controls compared to 17% of CRC cases, corresponding to a significantly increased CRC risk (OR: 2.17, 95% CI: 1.44-3.27). In this prospective nested case-control study, we observed a positive association between antibody responses to SGG and CRC development in serum samples taken before evident disease onset. Further work is required to establish the possibly etiological significance of these observations and whether SGG serology may be applicable for CRC risk stratification.

Matched MeSH terms: Bacterial Proteins/immunology
Fulltext Investigation on the conA binding properties of Klebsiella pneumoniae

Anuar AS, Tay ST

Trop Biomed, 2014 Dec;31(4):802-12.
PMID: 25776607 MyJurnal

Klebsiella pneumoniae is a healthcare-associated bacterial pathogen which causes severe diseases in immunocompromised individuals. Concanavalin A (conA), a lectin which recognizes proteins with mannose or glucose residues, has been reported to agglutinate K. pneumoniae and hence, is postulated to have therapeutical potential for K. pneumoniae-induced liver infection. This study investigated the conA binding properties of a large collection of clinical isolates of K. pneumoniae. ConA agglutination reaction was demonstrated by 94 (51.4%) of 183 K. pneumoniae isolates using a microtiter plate assay. The conA agglutination reactions were inhibited in the presence of 2.5 mg/ml D-mannose and 2.5 mg/ml glucose, and following pretreatment of the bacterial suspension with protease and heating at 80ºC. Majority of the positive isolates originated from respiratory specimens. Isolation of conA-binding proteins from K. pneumoniae ATCC 700603 strain was performed using conA affinity column and the conA binding property of the eluted proteins was confirmed by western blotting analysis using conA-HRP conjugates. Proteins with molecular weights ranging from 35 to 60 kDa were eluted from the conA affinity column, of which four were identified as outer membrane protein precursor A (37 kDa), outer membrane protein precursor C (40 kDa), enolase (45 kDa) and chaperonin (60 kDa) using mass spectrometry analysis. Several conA binding proteins (including 45 and 60 kDa) were found to be immunogenic when reacted with rabbit anti-Klebsiella antibody. The function and interplay of the conA binding proteins in bacterium-host cell relationship merits further investigation.

Matched MeSH terms: Bacterial Proteins/immunology
Fulltext Evaluation of recombinant antigens for diagnosis of melioidosis

Allwood EM, Logue CA, Hafner GJ, Ketheesan N, Norton RE, Peak IR, et al.

FEMS Immunol. Med. Microbiol., 2008 Oct;54(1):144-53.
PMID: 18657105 DOI: 10.1111/j.1574-695X.2008.00464.x

Burkholderia pseudomallei, the causative agent of melioidosis, is endemic to Southeast Asia and northern Australia. Clinical manifestations of the disease are diverse, ranging from chronic localized infection to acute septicaemia, with death occurring within 24-48 h after the onset of symptoms. Definitive diagnosis of melioidosis involves bacterial culture and identification, with results obtained within 3-4 days. This delayed diagnosis is a major contributing factor to high mortality rates. Rapid diagnosis is vital for successful management of the disease. This study describes the purification and evaluation of three recombinant antigenic proteins, BPSL0972, BipD and OmpA from B. pseudomallei 08, for their potential in the serodiagnosis of melioidosis using an indirect enzyme-linked immunosorbent assay (ELISA) method. The recombinant proteins were evaluated using 74 serum samples from culture-confirmed melioidosis patients from Malaysia, Thailand and Australia. In addition, 62 nonmelioidosis controls consisting of serum samples from clinically suspected melioidosis patients (n=20) and from healthy blood donors from an endemic region (n=18) and a nonendemic region (n=24) were included. The indirect ELISAs using BipD and BPSL0972 as antigens demonstrated poor to moderate sensitivities (42% and 51%, respectively) but good specificity (both 100%). In contrast, the indirect ELISA using OmpA as an antigen achieved 95% sensitivity and 98% specificity. These results highlight the potential for OmpA to be used in the serodiagnosis of melioidosis in an endemic area.

Matched MeSH terms: Bacterial Proteins/immunology
Does the Development of Vaccines Advance Solutions for Tuberculosis?

AlMatar M, Makky EA, AlMandeal H, Eker E, Kayar B, Var I, et al.

Curr Mol Pharmacol, 2019;12(2):83-104.
PMID: 30474542 DOI: 10.2174/1874467212666181126151948

BACKGROUND: Mycobacterium tuberculosis (Mtb) is considered as one of the most efficacious human pathogens. The global mortality rate of TB stands at approximately 2 million, while about 8 to 10 million active new cases are documented yearly. It is, therefore, a priority to develop vaccines that will prevent active TB. The vaccines currently used for the management of TB can only proffer a certain level of protection against meningitis, TB, and other forms of disseminated TB in children; however, their effectiveness against pulmonary TB varies and cannot provide life-long protective immunity. Based on these reasons, more efforts are channeled towards the development of new TB vaccines. During the development of TB vaccines, a major challenge has always been the lack of diversity in both the antigens contained in TB vaccines and the immune responses of the TB sufferers. Current efforts are channeled on widening both the range of antigens selection and the range of immune response elicited by the vaccines. The past two decades witnessed a significant progress in the development of TB vaccines; some of the discovered TB vaccines have recently even completed the third phase (phase III) of a clinical trial.
OBJECTIVE: The objectives of this article are to discuss the recent progress in the development of new vaccines against TB; to provide an insight on the mechanism of vaccine-mediated specific immune response stimulation, and to debate on the interaction between vaccines and global interventions to end TB.

Matched MeSH terms: Bacterial Proteins/immunology