Contamination, fraction, and source apportionment of heavy metals in sediment of an industrialized urban river in China.

In this study, we conducted an analysis of the heavy metal concentrations, health risk assessment, fraction and source interpretation in surface and core sediments from main stream of the Pearl River and Pearl River Estuary (RRE) area. Results showed that the higher deposited heavy metal concentrations in sediments occur at the Pearl River. The concentrations of heavy metals in surface sediments from the studied locations are in a descending order: Zn > Cr > Cu > Ni > Pb > Cd. Regarding chemical fractions, Cd showed the highest proportion of acid soluble fraction (F1) among all studied heavy metals. The high mobility of Cd poses a significant threat to water bodies and the surrounding environment. The potential ecological risk index (RI) showed the Pearl River sediments exhibited significantly higher values than the estuary sediments. Cd was found to be the primary contributor to potential ecological risk, accounting for 74% of RI. The health risk assessment showed the total hazard index (HI) for child was exceeded 1 mainly driven by Zn, indicating that the child population was at risk of non-carcinogenic effects. Besides, unacceptable carcinogenic risk in both Pearl River and estuary area were observed for children. The positive matrix factorization (PMF) model was used to ascertain sources of six heavy metals and apportion their contributions in sediments. The results showed that the source contributions of natural, industrial, and mixed sources from coal combustion and traffic emissions accounted for 39.81%, 34.10%, 26.10%.

Universal influenza vaccine based on conserved antigens provides long-term durability of immune responses and durable broad protection against diverse challenge virus strains in mice.

Current influenza vaccines rely on inducing antibody responses to the rapidly evolving hemagglutinin (HA) and neuraminidase (NA) proteins, and thus need to be strain-matched. However, predictions of strains that will circulate are imperfect, and manufacturing of new vaccines based on them takes months. As an alternative, universal influenza vaccines target highly conserved antigens. In proof of concept studies of universal vaccine candidates in animal models challenge is generally conducted only a short time after vaccination, but protective immunity lasting far longer is important for the intended public health impact. We address the challenge of providing long-term protection. We demonstrate here broad, powerful, and long-lasting immune protection for a promising universal vaccine candidate. A single intranasal dose of recombinant adenoviruses (rAd) expressing influenza A nucleoprotein (A/NP) and matrix 2 (M2) was used. Extending our previous studies of this type of vaccine, we show that antibody and T-cell responses persist for over a year without boosting, and that protection against challenge persists a year after vaccination and remains broad, covering both group 1 and 2 influenza A viruses. In addition, we extend the work to influenza B. Immunization with influenza B nucleoprotein (B/NP)-rAd also gives immune responses that last a year without boosting and protect against challenge with influenza B viruses of mismatched HA lineages. Despite host immunity to adenoviral antigens, effective readministration is possible a year after primary vaccination, as shown by successful immunization to a transgene product the animals had not seen before. Protection against challenge with divergent and highly pathogenic A/H7N9 virus was weaker but was enhanced by a second dose of vaccine. Thus, this mucosal vaccination to conserved influenza antigens confers very long-lasting immune protection in animals against a broad range of influenza A and B viruses.

Pregnancy level of estradiol attenuated virus-specific humoral immune response in H5N1-infected female mice despite inducing anti-inflammatory protection.

Estradiol, a major female steroid produced during pregnancy, has been reported to protect ovariectomized animals against H1N1 influenza infections via its anti-inflammatory effects. However, it remains unclear why pregnant women with high gestational estradiol levels are highly susceptible to influenza infections. This study was aimed to investigate the effects of pregnancy level of estradiol on female immunity against H5N1 infection in Balb/c mice. A sex-dependent susceptibility to H5N1 infection (higher morbidity and higher mortality) was observed in both pregnant and non-pregnant female mice as compared to male mice. Subcutaneous implantation of estradiol pellets increased serum estradiol concentrations of non-pregnant female mice to the pregnancy level. These mice were protected from H5N1 infection through downregulation of pulmonary pro-inflammatory cytokines. However, the production of virus-specific antibodies after infection was significantly delayed in estradiol-implanted mice when compared to placebos. Virus-specific IgG-secreting and IL-4-secreting cells were also reduced in estradiol-implanted mice. Similarly, lower antibody titers to seasonal vaccine antigens were found in pregnant women as compared to non-pregnant females without hormone usage. Our results indicate that estradiol levels equivalent to those found during pregnancy have divergent effects on female immunity against influenza, highlighting the importance of vaccination during pregnancy to prevent severe influenza infections.

Influenza virus NS1 protein mutations at position 171 impact innate interferon responses by respiratory epithelial cells.

The influenza virus NS1 protein interacts with a wide range of proteins to suppress the host cell immune response and facilitate virus replication. The amino acid sequence of the 2009 pandemic virus NS1 protein differed from sequences of earlier related viruses. The functional impact of these differences has not been fully defined. Therefore, we made mutations to the NS1 protein based on these sequence differences, and assessed the impact of these changes on host cell interferon (IFN) responses. We found that viruses with mutations at position 171 replicated efficiently but did not induce expression of interferon genes as effectively as wild-type viruses in A459 lung epithelial cells. The decreased ability of these NS1 mutant viruses to induce IFN gene and protein expression correlated with decreased activation of STAT1 and lower levels of IFN-stimulated gene (ISG) expression. These findings demonstrate that mutations at position 171 in the NS1 protein result in decreased expression of IFN and ISGs by A549 cells. Consequently, these viruses may be more virulent than the parental strains that do not contain mutations at position 171 in the NS1 protein.

Pandemic Influenza A (H1N1) Virus Infection Increases Apoptosis and HIV-1 Replication in HIV-1 Infected Jurkat Cells.

Influenza virus infection has a significant impact on public health, since it is a major cause of morbidity and mortality. It is not well-known whether influenza virus infection affects cell death and human immunodeficiency virus (HIV)-1 replication in HIV-1-infected patients. Using a lymphoma cell line, Jurkat, we examined the in vitro effects of pandemic influenza A (H1N1) virus (pH1N1) infection on cell death and HIV-1 RNA production in infected cells. We found that pH1N1 infection increased apoptotic cell death through Fas and Bax-mediated pathways in HIV-1-infected Jurkat cells. Infection with pH1N1 virus could promote HIV-1 RNA production by activating host transcription factors including nuclear factor kappa-light-chain-enhancer of activated B cells (NF-ĸB), nuclear factor of activated T-cells (NFAT) and activator protein 1 (AP-1) through mitogen-activated protein kinases (MAPK) pathways and T-cell antigen receptor (TCR)-related pathways. The replication of HIV-1 latent infection could be reactivated by pH1N1 infection through TCR and apoptotic pathways. These data indicate that HIV-1 replication can be activated by pH1N1 virus in HIV-1-infected cells resulting in induction of cell death through apoptotic pathways.

Novel pandemic influenza A (H1N1) virus infection modulates apoptotic pathways that impact its replication in A549 cells.

It is not well-known whether apoptosis signaling affects influenza virus infection and reproduction in human lung epithelial cells. Using A549 cell line, we studied the relationship of some apoptosis-associated molecules with novel pandemic influenza A (H1N1) virus, A/California/04/2009. Infected cells displayed upregulated Fas ligand, activated FADD and caspase-8, and downregulated FLIP in the extrinsic apoptotic pathway. p53 expression increased and Bcl-XL expression decreased in the intrinsic pathway. Expression of pre-apoptotic molecules (FasL, FADD, and p53) increased virus replication, while inhibition of activity of FADD, caspase-8 and caspase-3, and expression of anti-apoptotic proteins (FLIP and Bcl-XL) decreased virus replication. p38, ERK and JNK from MAPK pathways were activated in infected cells, and inhibition with their inhibitors diminished virus replication. In the p38 superfamily, p38α expression increased viral RNA production, while expression of p38ß and p38γ decreased. These data indicated that influenza virus induces apoptotic signaling pathways, which benefit virus replication.

Establishment of retroviral pseudotypes with influenza hemagglutinins from H1, H3, and H5 subtypes for sensitive and specific detection of neutralizing antibodies.

Pseudotype reporter viruses provide a safe, quantitative, and high-throughput tool for assessing antibody neutralization for many viruses, including high pathogenicity H5 and H7 influenza A strains. However, adapting this system to other influenza subtypes has been hampered by variations in the protease cleavage site of hemagglutinin (HA) that make it less susceptible to the cleavage required for infectivity. In this report several proteases, reporter vectors, and cell substrates were evaluated while optimizing pseudovirus production, and robust methods were established for sensitive and specific neutralization of pseudotypes carrying influenza H1, H3, and H5 subtype HA that correlates well with titers obtained in microneutralization assays involving replicating influenza virus These findings should facilitate broad use of HA-pseudotypes that remove the need for infectious virus in a range of applications, including neutralization assays for serological surveys of viral infection and evaluations of vaccine sera.

Matrix protein 2 vaccination and protection against influenza viruses, including subtype H5N1.

Changes in influenza viruses require regular reformulation of strain-specific influenza vaccines. Vaccines based on conserved antigens provide broader protection. Influenza matrix protein 2 (M2) is highly conserved across influenza A subtypes. To evaluate its efficacy as a vaccine candidate, we vaccinated mice with M2 peptide of a widely shared consensus sequence. This vaccination induced antibodies that cross-reacted with divergent M2 peptide from an H5N1 subtype. A DNA vaccine expressing full-length consensus-sequence M2 (M2-DNA) induced M2-specific antibody responses and protected against challenge with lethal influenza. Mice primed with M2-DNA and then boosted with recombinant adenovirus expressing M2 (M2-Ad) had enhanced antibody responses that crossreacted with human and avian M2 sequences and produced T-cell responses. This M2 prime-boost vaccination conferred broad protection against challenge with lethal influenza A, including an H5N1 strain. Vaccination with M2, with key sequences represented, may provide broad protection against influenza A.

Targeted infection of HIV-1 Env expressing cells by HIV(CD4/CXCR4) vectors reveals a potential new rationale for HIV-1 mediated down-modulation of CD4.

BACKGROUND: Efficient targeted gene transfer and cell type specific transgene expression are important for the safe and effective expression of transgenes in vivo. Enveloped viral vectors allow insertion of exogenous membrane proteins into their envelopes, which could potentially aid in the targeted transduction of specific cell types. Our goal was to specifically target cells that express the T cell tropic HIV-1 envelope protein (Env) using the highly specific interaction of Env with its cellular receptor (CD4) inserted into the envelope of an HIV-1-based viral vector. RESULTS: To generate HIV-1-based vectors carrying the CD4 molecule in their envelope, the CD4 ectodomain was fused to diverse membrane anchors and inserted together with the HIV-1 coreceptor CXCR4 into the envelopes of HIV-1 vector particles. Independent of the type of CD4 anchor, all chimeric CD4 proteins inserted into HIV-1 vector envelopes and the resultant HIV(CD4/CXCR4) particles were able to selectively confer neomycin resistance to cells expressing the fusogenic T cell tropic HIV-1 Env protein. Unexpectedly, in the absence of Env on the target cells, all vector particles carrying the CD4 ectodomain anchored in their envelope adhered to various cell types without infecting these cells. This cell adhesion was very avid. It was independent of the presence of Env on the target cell, the type of CD4 anchor or the presence of CXCR4 on the particle. In mixed cell populations with defined ratios of Env+/Env- cells, the targeted transduction of Env+ cells by HIV(CD4/CXCR4) particles was diminished in proportion to the number of Env- cells. CONCLUSION: Vector diversion caused by a strong, non-selective cell binding of CD4+-vector particles effectively prevents the targeted transduction of HIV-1 Env expressing cells in mixed cell populations. This Env-independent cell adhesion severely limits the effective use of targeted HIV(CD4/CXCR4) vectors designed to interfere with HIV-1 replication in vivo. Importantly, the existence of this newly described and remarkably strong CD4-dependent cell adhesion suggests that the multiple viral efforts to reduce CD4 cell surface expression may, in part, be to prevent cell adhesion to non-target cells and thereby to increase the infectivity of viral progeny. Preventing CD4 down-modulation by HIV-1 might be an effective component of a multi-faceted antiviral strategy.