Differential Immune Responses and Protective Effects in Avirulent Mycobacterial Strains Vaccinated BALB/c Mice.

Screening live mycobacterial vaccine candidates is the important strategy to develop new vaccines against adult tuberculosis (TB). In this study, the immunogenicity and protective efficacy of several avirulent mycobacterial strains including Mycobacterium smegmatis, M. vaccae, M. terrae, M. phlei, M. trivial, and M. tuberculosis H37Ra were compared with M. bovis BCG in BALB/c mice. Our results demonstrated that differential immune responses were induced in different mycobacterial species vaccinated mice. As BCG-vaccinated mice did, M. terrae immunization resulted in Th1-type responses in the lung, as well as splenocytes secreting IFN-γ against a highly conserved mycobacterial antigen Ag85A. M. smegmatis also induced the same splenocytes secreting IFN-γ as BCG and M. terrae did. In addition, M. terrae and M. smegmatis-immunized mice predominantly increased expression of IL-10 and TGF-ß in the lung. Most importantly, mice vaccinated with H37Ra and M. vaccae could provide the same protection in the lung against virulent M. tuberculosis challenge as BCG. The result may have important implications in developing adult TB vaccine.

Immunogenicity and protective efficacy of a novel recombinant BCG strain overexpressing antigens Ag85A and Ag85B.

Recombinant Bacillus Calmette-Guérin (rBCG) strain is the promising vaccine candidate for tuberculosis (TB) prevention, which aims at providing more enduring and enhanced protection than the parental BCG vaccine. In this study, three rBCG strains overexpressing immunodominant antigens Ag85B (rBCG::85B), Ag85A (rBCG::85A), or both (rBCG::AB) of Mycobacterium tuberculosis were constructed, respectively. rBCG strains showed higher level of overexpression of Ag85A and/or Ag85B proteins than BCG containing empty vector pMV261(rBCG::261), which had low levels of endogenous expression of both proteins as expected. rBCG::AB strain could provide the strongest short-term and long-term protection in the lung against intravenous infection with virulent M. tuberculosis than rBCG::261 control and other two rBCG strains overexpressing single antigen. The stronger and longer-lasting protection provided by rBCG::AB than rBCG::261 was correlated with systemic in vitro antigen-specific IFN-γ responses. Therefore, our results indicate that rBCG::AB could be a very promising TB vaccine candidate and should be further evaluated for the preclinical test.

A DNA vaccine expressing CFP21 and MPT64 fusion protein enhances BCG-induced protective immunity against Mycobacterium tuberculosis infection in mice.

The efficacy of Bacillus Calmette-Guérin (BCG) vaccine in preventing adult tuberculosis (TB) is highly variable. Genetic differences between BCG vaccine substrains, which can be divided into early strains and late strains based on the loss of region of difference two (RD2), may result in the variability and BCG substrains. The effect of lack of RD2 on the protective efficacy of BCG substrains against TB remains unknown. In this study, we demonstrated that CFP21 and MPT64(rCM) fusion protein, encoded by RD2 of Mycobacterium tuberculosis, could stimulate higher level of interferon (IFN)-γ in tuberculin skin test (TST)-positive healthy population than in TST-negative healthy population. Compared with naive mice challenged with virulent M. tuberculosis H37Rv, C57BL/6 mice vaccinated with pcD2164 DNA expressing rCM protein resulted in a greater decrease in the bacterial load of lung. Moreover, pcD2164 could boost the protective immunity in mice primed by BCG than BCG alone or DNA vaccination alone, as evidenced by lower bacterial load in the lung tissue and reduced lung pathology. The protection induced by BCG prime-DNA vaccine boost strategy was associated with significant increases in rCM protein-specific IFN-γ. Therefore, our results clearly indicate that the loss of RD2 has an important influence on the protective efficacy of different BCG substrains. These findings will benefit the optimal choice of BCG substrain for neonatal immunization and rational design of new vaccines for the prevention of TB.

A preparatively convenient ligand-free catalytic PEG 2000 Suzuki-Miyaura coupling.

A ligand-free Suzuki-Miyaura reaction for the cross-coupling of aryl and heteroaryl bromides with aryl and heteroarylboronic acids has been developed utilizing catalytic polyethylene glycol 2000 (PEG 2000). This preparatively convenient system afforded the corresponding cross-coupled products in good to excellent isolated yields after a simple aqueous workup. Transmission electron microscopy (TEM) analysis of the Pd-PEG 2000 catalyst system revealed in situ-generated palladium nanoparticles after only 1 min of reaction.

Cyanidin 3-rutinoside and cyanidin 3-xylosylrutinoside as primary phenolic antioxidants in black raspberry.

Anthocyanin constituents in black raspberries (Rubus occidentalis L.) were investigated by HPLC-DAD, and their involvement as potent, significant antioxidants in black raspberries was demonstrated by three common antioxidant assays (FRAP, DPPH, ABTS) in this study. Five anthocyanins were present in black raspberries: cyanidin 3-sambubioside, cyanidin 3-glucoside, cyanidin 3-xylosylrutinoside, cyanidin 3-rutinoside, and pelargonidin 3-rutinoside. Their identities and structures, with particular emphasis on cyanidin 3-xylosylrutinoside, were confirmed by NMR spectroscopy. Two of these anthocyanins, cyanidin 3-rutinoside and cyanidin 3-xylosylrutinoside, predominated, comprising 24-40 and 49-58%, respectively, of the total anthocyanins in black raspberries. On the basis of both potency and concentration, cyanidin 3-rutinoside and cyanidin 3-xylosylrutinoside were found to be the significant contributors to the antioxidant systems of black raspberries. These findings indicate that these two anthocyanin compounds may function as the primary phenolic antioxidants in black raspberries. These two compounds exhibit potential biological activities that may be exploited in conjunction with other naturally occurring bioactive compounds in black raspberry fruit-based products used in clinical trials for the treatment of various types of cancer.

Fabrication of Cd(OH)2 nanorings by ultrasonic chiselling on Cd(OH)2 nanoplates.

Cd(OH)2 nanorings were successfully fabricated from Cd(OH)2 nanoplates by ultrasonic chiselling, a unique effect of the sonochemical process that has never been reported before.

Fabrication of a hydrogen peroxide biosensor based on a self-assemble composite oxide film.

A titania film with horseradish peroxidase (HRP) was immobilized on indium tin oxide (ITO) electrodes to act as a biosensor of hydrogen peroxide via the self-assembling and sol-gel route. The film was characterized by the atomic functional microscopy, electrochemical and UV-vis spectroscopy methods. The resulting biosensor exhibited fast amperometric response and good stability to hydrogen peroxide (H2O2). The linear range for H2O2 determination was from 2 x10(-6) to 1.45 x 10(-3) M, with a detection limit of 4 x10(-6) M based on S/N=3. The apparent Michaelis-Menten constant of the biosensor to H2O2 was estimated to be 1.5 mM, showing the HRP on the films had the higher biologic activities.

Development and evaluation of a new interferon-gamma release assay for the diagnosis of tuberculosis infection in HIV-infected individuals in China.

BACKGROUND: Human immunodeficiency virus (HIV)-infected individuals are at high risk of contracting tuberculosis (TB) disease, and current methods for diagnosing TB infection are less effective in this population. We developed and evaluated a new interferon-gamma release assay (IGRA), named A.TB, in HIV-infected individuals, with and without active TB, in a setting of high TB burden and low HIV prevalence. METHODS: A total of 255 subjects were divided into 3 groups according to their HIV and TB status: HIV+ without active TB (n = 123), HIV+/TB+ (n = 79), and HIV-/TB+ (n = 65). The A.TB assay was performed in parallel with the QuantiFERON-TB Gold In-Tube (QFT-GIT) and tuberculin skin test (TST). RESULTS: The positive rate was 59.3% (n = 123) by A.TB and 53.8% (n = 106) by QFT-GIT. We observed a strong concordance of 81.2% (k = 0.612) between the two IGRAs. The QFT-GIT results were affected by low CD4(+) cell count (p = 0.013), while A.TB results were not. A.TB was also performed in patients with active TB (n = 65) and patients with active TB and HIV co-infection (n = 79). The sensitivity of A.TB in these groups was 80.0% and 81.0%, respectively. CONCLUSION: The A.TB results were not affected by low CD4(+) cell count in the co-infected cohort. With further evaluation, A.TB may prove to be a valuable tool for diagnosing TB in HIV-infected patients.

Enhanced protection against tuberculosis by vaccination with recombinant BCG over-expressing HspX protein.

Immunization with Mycobacterium bovis Bacille Calmette-Guerin (BCG) did not induce adequate Th1 responses to the latency antigen, HspX of M. tuberculosis. To increase the immunogenicity and protective efficacy of BCG, a recombinant BCG strain over-expressing antigen HspX (rBCG::X) was constructed. The recombinant strain rBCG::X expressed high levels of both HspX protein in the cytosol and Ag85B protein in the cytosol and supernatant. Mice vaccinated with rBCG::X produced a more consistent and enduring protective effect against infection with M. tuberculosis, showing lower bacterial load in lung and less severe lung pathology, than the control mice vaccinated with BCG strain containing the vector pMV261. The long-term protection induced by rBCG::X was associated with significant increases in antigen-specific IFN-gamma to both HspX and Ag85B proteins, while PPD-specific IFN-gamma responses declined. Our results suggest that latency antigens of M. tuberculosis may be promising targets for developing more effective recombinant BCG strains to protect against TB.

Differential immunogenicity and protective efficacy of DNA vaccines expressing proteins of Mycobacterium tuberculosis in a mouse model.

BALB/c mice were vaccinated three times (2-week intervals) with plasmid DNA separately encoding antigen Ag85B, ESAT-6 or Ag85A from Mycobacterium tuberculosis. The protective efficacy of these DNA vaccines against intravenous M. tuberculosis H37Rv challenge infection was measured by counting bacterial loads in spleen and lung and recording changes in lung pathology. The splenocyte proliferative response to the corresponding antigens and antigen-specific interferon (IFN)-gamma secreted by splenocytes of the vaccinated mice were also detected. We found a clear hierarchy of protective efficacies among the three DNA vaccines tested in this study. Plasmid DNA encoding Ag85A provided the strongest protection and showed the least change in lung pathology, followed by plasmid DNAs encoding Ag85B and ESAT-6. However, DNA-85B reduced comparative bacterial load in lung tissue, as did DNA-85A. Compared to the control group, protective efficacies conferred by different DNA vaccines were consistent with the lymphoproliferative responses to the corresponding antigens as well as the secretions of antigen-specific IFN-gamma. Our study demonstrates that both Ag85A and Ag85B are the most promising of the candidate antigens tested for future TB vaccine development.

An improved whole-blood gamma interferon assay based on the CFP21-MPT64 fusion protein.

Differentiation of latent tuberculosis infection (LTBI) from a healthy, unexposed population plays a vital role in the strategy of controlling and eliminating tuberculosis (TB). Both CFP21 and MPT64, antigens encoded by the RD2 region which are restricted in the Mycobacterium tuberculosis complex, are TB-specific diagnostic candidate antigens. In this study, we designed a fusion protein by linking both CFP21 and MPT64 with a 15-amino-acid peptide, (G(4)S(1))(3), and overexpressed the fusion protein in Escherichia coli. A new whole-blood gamma interferon assay based on the recombinant fusion protein, CFP21-MPT64 (rCM-WBIA), was developed and compared with the tuberculin skin test (TST) for screening of LTBI in household contacts of patients with sputum-positive TB. rCM-WBIA had a slightly higher sensitivity (66.7%; 24/36 contacts) than that of the TST (61.1%; 22/36 contacts) for household contacts. We found that rCM-WBIA had a very high sensitivity (90.9%) and specificity (71.4%) for LTBI detection compared with TST. The overall agreement between rCM-WBIA and TST was 83.3% (k = 0.64); rCM-WBIA positivity was associated with a larger TST induration. These results suggest that rCM-WBIA, based on the recombinant fusion protein CFP21-MPT64, is a promising alternative diagnostic tool for detection of LTBI.

Heterostructured Bi2Se3 nanowires with periodic phase boundaries.

Single and multijunction nanowires with diameters of 10-40 nm were synthesized by an electrically assisted sonochemical method in aqueous solution at room temperature. By properly controlling the reaction conditions and reactants, this method opens a new strategy towards the fabrication of one-dimensional superlattices in nanowires under ambient conditions. Such a chemical approach provides a promising and simple way to synthesize high-performance building blocks for device applications.