High postnatal exposures to polybrominated diphenyl ethers (PBDEs) and polychlorinated biphenyls (PCBs) via breast milk in California: does BDE-209 transfer to breast milk?

Breast milk samples collected during 2003-2005 from 82 first-time mothers in 24 communities located throughout California contained levels of polybrominated diphenyl ethers (∑(tri-hexa (8))PBDEs; median = 53.3 ng/g lw, range = 9.60-1291) and polychlorinated biphenyls (∑(12)PCBs; median = 73.4 ng/g lw, range = 22.2-433) that are among the highest in the world. PBDE levels varied 100-fold. BDE-47 was the dominant PBDE congener, with levels exceeding the U.S.EPA Reference Dose (RfD) for neurodevelopmental toxicity (100 ng/kg/day) in most (60%) breast milk samples. In some samples, BDE-209 (2/82) and/or BDE-153 (5/82) were the dominant congeners, suggesting that BDE-209 can transfer to breast milk and/or break down in the mother and transfer to the nursing infant as the lower-brominated PBDEs associated with adverse effects. PBDE levels in California breast milk are approaching those of PCBs, and the trend PBDEs > PCBs may continue as PBDEs migrate from products to the indoor and outdoor environments.

A blocking ELISA for the detection of antibodies to psittacine beak and feather disease virus (BFDV).

Currently, the only diagnostic test available routinely for the sero-diagnosis of BFDV is the haemagglutination-inhibition (HI) assay. This test, whilst useful and applicable to samples from a wide range of psittacine birds, is not an ideal assay; it requires erythrocytes from live animals, virus purified from the feathers of infected birds and polyclonal antibody preparations in order to perform the assay. Variations in these reagents make consistency between tests difficult to achieve, underscoring the need for a new test with standardised reagents for the sero-diagnosis of BFDV infection which has led to the development of an antibody response. The methods used to develop a novel "blocking" (or "competitive") ELISA (bELISA) for the detection of anti-BFDV antibodies in psittacine sera are presented in this paper. The assay was developed using a baculovirus-expressed recombinant BFDV capsid protein and a newly developed monoclonal antibody raised against this protein. The assay was then validated with 160 samples from eastern long-billed corellas (Cacatua tenuiostris) vaccinated with the recombinant capsid protein and challenged with live virus and samples from 82 cockatiels known to be HI negative. The bELISA described in this study is a sensitive and specific diagnostic test and should have wide application for the sero-diagnosis of BFDV.

A quantitative, real-time polymerase chain reaction assay for beak and feather disease virus.

PCR-based assays for the detection of BFDV DNA are in widespread use throughout the world. Quantitative real-time PCR assays are extremely sensitive and have the advantages over standard PCR assays that they do not require post-reaction processing to visualise PCR products and can quantify the amount of DNA present in a sample. This study describes a quantitative real-time PCR assay for the detection of BFDV DNA, using primers designed to amplify a conserved 81 bp fragment of ORFV1 and SYTO9, a fluorescent intercalating dye. A synthetic oligonucleotide was used to make standard curves for the quantitation of viral load in blood and feather preparations. The assay was very sensitive, with a detection limit of 50 copies/microL. The assay was developed using DNA extracts from the feathers of 10 different species of birds which had tested BFDV-positive previously and was validated with blood and feather samples from corellas vaccinated with an experimental BFDV vaccine, then challenged with live virus. Viral DNA was detected consistently in the blood of all control (non-vaccinated) birds and in some vaccinated birds. Contamination of the environment with feather dander from BFDV-infected birds meant that feather preparations used for the haemagglutination assay were unreliable for the detection and quantitation of viral excretion. Nonetheless, the assay should prove to be a useful and sensitive test for the detection of viral DNA in a range of samples.

Assessment of recombinant beak and feather disease virus capsid protein as a vaccine for psittacine beak and feather disease.

Beak and feather disease virus (BFDV) is a significant pathogen of wild Australasian and African psittacine birds. We assessed the immunogenicity of recombinant BFDV capsid (recBFDVcap) to protect against the development of psittacine beak and feather disease (PBFD). Long-billed corellas (Cacatua tenuirostris) (n=13) received (by injection) 1 ml vaccine containing 10 microg recBFDVcap on day 0 and 0.4 ml vaccine containing 66.8 microg recBFDVcap on day 11. All vaccinated corellas and five non-vaccinated control corellas were given 0.4 ml BFDV suspension [titre=log(2) 12 haemagglutination units (HAU) 50 microl(-1)] intramuscularly and 0.1 ml orally 16 days after booster vaccination. Blood was collected during the vaccination period and blood and feathers were collected after BFDV administration. Testing of blood samples included BFDV DNA detection by PCR and quantitative PCR (qPCR) as well as antibody detection by haemagglutination inhibition (HI) and on feather samples, BFDV DNA and antigen was detected by haemagglutination (HA) and qPCR. Four of 97 blood samples collected from vaccinated birds after virus challenge tested positive by PCR, whereas 17 of 35 samples taken from non-vaccinated control corellas tested positive. Vaccinated birds did not develop feather lesions, had only transient PCR-detectable viraemia and had no evidence of persistent infection 270 days post-challenge using PCR, histopathology and immunohistochemistry. Non-vaccinated control corellas developed transient feather lesions and had PCR, HI and HA test results consistent with PBFD. They were BFDV PCR-positive for up to 41 days post-challenge and qPCR demonstrated reduced virus replication in vaccinated birds compared with non-vaccinated control birds.

Beak and feather disease virus infection in cockatiels (Nymphicus hollandicus).

Psittacine beak and feather disease is known to occur in a wide range of psittacine species; however, there are no scientific or credible anecdotal reports of psittacine beak and feather disease occurring in the cockatiel (Nymphicus hollandicus) despite it being one of the world's most commonly kept companion bird species. Consequently, this has resulted in speculation that the species may have some innate resistance to beak and feather disease virus (BFDV) infection. To investigate this hypothesis we conducted a survey of cockatiels (n=88) at commercial aviaries to investigate whether BFDV infection occurs in cockatiels, and found that all birds were virus-free by polymerase chain reaction and haemagglutination assay and had no detectable antibody titre by haemagglutination-inhibition assay. In addition to this, we sequenced the genome of two BFDV isolates obtained from diseased cockatiel feathers and performed cross-reactivity assays using virus eluted from these feathers and sera from naturally immune psittacine birds. Serological cross-reactivity results and phylogenetic analysis of the nucleotide sequences indicated that the cockatiel virus isolates were serologically and genetically different to other BFDV isolates. This is the first paper to report evidence of an antigenically distinct BFDV in psittacine birds.

Development and applications of a monoclonal antibody to a recombinant beak and feather disease virus (BFDV) capsid protein.

The development of diagnostic assays for detecting beak and feather disease virus (BFDV) has traditionally been hampered by the difficulty associated with producing suitable reagents, namely purified virus and polyclonal antibodies. In an effort to develop a consistent and standardised source of antibody, a monoclonal antibody to a recombinant BFDV capsid protein has been developed and its use in western blotting, immunohistochemistry (IHC), ELISA and haemagglutination-inhibition (HI) assays characterised. The antibody was specific for both the recombinant BFDV capsid protein and the whole virus and had similar optimal titres when used in western blotting and IHC. The antibody also had HI activity and detected BFDV virus from three genera of psittacine birds, including the recently described cockatiel BFDV isolate. The monoclonal antibody should have widespread application in both research and the development of diagnostic assays for BFDV.

Depuration of polybrominated diphenyl ethers (PBDEs) and polychlorinated biphenyls (PCBs) in breast milk from California first-time mothers (primiparae).

BACKGROUND: Little is known about the rates of loss (depuration) of polybrominated diphenyl ethers (PBDEs) and polychlorinated biphenyls (PCBs) from mothers during lactation. Depuration rates affect infant exposure to chemicals during breast-feeding, and fetal and lactational transfers during subsequent pregnancies. OBJECTIVE: Our objective in this study was to estimate depuration rates of PBDEs and PCBs using serial samples of breast milk. METHOD: Nine first-time mothers (primiparae) each collected samples at 4, 6, 8, 12, 16, 20, and 24 weeks after birth. Nine additional primiparae each collected two samples at varying time intervals (18 to > 85 weeks after birth). Analytical precision was assessed to evaluate the accuracy of measured monthly percentage declines in PBDEs and PCBs. RESULTS: The four major PBDE congeners decreased 2 or 3% +/- 1% per month over the 6-month period. These decreases were consistent over a 50-fold range (21-1,330 ng/g lipid weight) of initial PBDE concentrations in breast milk. The change in PCB-153 ranged from + 0.3% to -0.6% per month, with heterogeneous slopes and greater intraindividual variability. PBDE and PCB concentrations declined 1% per month over longer periods (up to 136 weeks). CONCLUSIONS: Our data indicate that PBDEs and PCBs are not substantially (4-18%) reduced in primiparae after 6 months of breast-feeding. Consequently, the fetal and lactational exposures for a second child may not be markedly lower than those for the first. Participants were volunteers from a larger study population (n = 82), and were typical in their PBDE/PCB levels and in many demographic and lifestyle factors. These similarities suggest that our results may have broader applicability.

A promoter with bidirectional activity is located between TLX1/HOX11 and a divergently transcribed novel human gene.

The chromosomal region 10q24 is involved in reciprocal translocations with one of the T-cell receptor loci in a significant proportion of human T-cell acute lymphoblastic leukemias. The breakpoints of these rearrangements cluster immediately upstream of the TLX1 homeobox gene and lead to its transcriptional activation. Genomic analysis using sequences located on the opposite side of the breakpoint cluster region identified a novel gene composed of three exons that is oriented in a head-to-head manner with TLX1. The novel gene, named TDI (TLX1 divergent) codes for a 1.9 kb transcript with an atypically long 5' leader sequence. Although predicted to be a transcriptional regulator of 13.4 kDa, the TDI protein has no significant sequence similarity to any known protein. The TLX1 and TDI genes are separated by a short spacer of only 161 bp that contains numerous GC boxes and a centrally located CCAAT box embedded within a CpG island. Using luciferase as the reporter in transient transfection assays, the intergenic region was found to be a functional promoter with robust bidirectional activity. TLX1 and TDI thus appear to represent another example of a divergently transcribed gene pair whose expression is regulated by a common promoter. Our finding that TDI is transcriptionally co-activated in leukemic cells that aberrantly express TLX1, additionally suggests that it may have the potential to act as a co-operating oncogene in leukemogenesis.

Polybrominated diphenyl ethers (PBDEs) and polychlorinated biphenyls (PCBs) in breast milk from the Pacific Northwest.

Breast milk samples from 40 first-time mothers from the Pacific Northwest of the US and Canada were analyzed for polybrominated diphenyl ethers (PBDEs) and polychlorinated biphenyls (PCBs). Total PBDEs (summation operator PBDEs), calculated by summing values for the 12 PBDEs congeners analyzed, ranged from 6 to 321 ppb (lipid weight) (mean=96 ppb; median=50 ppb). In approximately 40% of the women (15/40), summation operator PBDEs>100 ppb lw in their milk, and four samples had levels >250 ppb lw. PBDE 47 was the dominant congener in most samples, whereas PBDE 153 was predominant in a few (3/40). summation operator PCBs were calculated by summing values for the 82 PCB congeners analyzed, and ranged from 49 to 415 ppb (lipid weight) (mean=147 ppb; median=126 ppb). approximately 30% of the mothers (13/40) have summation operator PBDEs> summation operator PCBs in their milk samples, and approximately 65% (25/40) have BDE 47>PCB 153 in breast milk samples, with BDE 47 averaging 3-fold greater levels than PCB 153. Clearly, the lower brominated PBDEs are surpassing PCBs as a major environmental concern in North America, and are likely affecting significant portions of the populations in these regions. PBDEs have become a major persistent organic pollutant. However, there are no positive correlations between levels of summation operator PBDEs and summation operator PCBs, or between levels of PBDE 47 and PCB 153, suggesting there may be some differences in exposure pathways for PBDEs and PCBs in humans.

Baculovirus expression of beak and feather disease virus (BFDV) capsid protein capable of self-assembly and haemagglutination.

Beak and feather disease virus (BFDV) is a common avian circovirus infection of wild Psittaciformes and is a recognised threat to endangered psittacine species. Currently, there is a requirement to develop BFDV antigen for diagnostic purposes and since efforts to propagate BFDV in vitro have so far been unsuccessful the entire coding region of BFDV ORF C1 was expressed in Sf9 insect cells using a baculovirus expression system. The entire coding region of BFDV ORF C1, the presumptive capsid, was expressed in Sf9 insect cells using baculovirus expression system. Electron microscopic examination of negatively stained material demonstrated that the recombinant protein self-assembled to produce virus-like particles (VLPs) thus confirming that ORF C1 is likely to be the sole determinant for capsid construction in vivo. BFDV VLPs also possessed haemagglutinating activity which provides further evidence that self-assembled BFDV VLPs retain receptor mediated biological activity and that the determinants for BFDV haemagglutination activity rely solely on the capsid protein. The recombinant protein reacted with anti-BFDV sera from naturally immune parrots and cockatoo and from chickens experimentally inoculated with native BFDV in both Western blots and haemagglutination inhibition (HI) assay. BFDV VLPs were also a suitable replacement antigen for serological detection of BFDV antibody by HI.

Protective immunity to cytomegalovirus (CMV) retinitis in AIDS is associated with CMV-specific T cells that express interferon- gamma and interleukin-2 and have a CD8+ cell early maturational phenotype.

To determine potential correlates of immune recovery from AIDS-related cytomegalovirus retinitis (CMVR), multiparameter flow cytometry was used to characterize CMV-specific T cells from subjects with CMVR. Individuals with active retinitis were compared with those who had been clinically immunorestored by antiretroviral therapy and had > or =2 years of ophthalmologic follow-up without anti-CMV therapy or retinitis reactivation or progression. In comparison with patients with active retinitis, immunorestored patients had higher circulating CD4(+) and CD8(+) T cells expressing interleukin-2 and interferon- gamma in response to combined CMV pp65 and IE1 peptide pool stimulation. CD4(+) T cell responses were predominantly to pp65, whereas CD8(+) T cell responses were predominantly to IE. Immunorestored patients, compared with patients with active retinitis, had increased levels of circulating CMV-specific CD8(+) T cells with "early" (CD27(+)CD28(+)CD45RA(+), CD27(+)CD28(+)CD45RA(-)) and "intermediate" (CD27(-)CD28(+)CD45RA(-)) phenotypes. Recovery from AIDS-related CMVR after the initiation of antiretroviral therapy may be mediated by CMV-specific CD4(+) and CD8(+) T cells capable of promoting antigen-specific CD8(+) T cell proliferation.

Variability and gender differences in memory T cell immunity to varicella-zoster virus in healthy adults.

Latent varicella zoster virus (VZV) can reactivate and cause zoster, the prevention of which relies upon cellular immunity to VZV. To assess temporal variation of VZV cell-mediated immunity in healthy naturally immune adults, we evaluated VZV-specific responder cell frequencies (RCF) longitudinally over 1 year in each of 25 adults. VZV-specific CD4+ T cells were detected (p < 0.003) and showed minimal variability in RCF. Additional analysis of VZV T cell RCF revealed differences between genders, with only males (p < 0.005) having detectable VZV-specific memory CD4+ T cell responses by this method. Taken together, results suggest that further studies regarding immunization of younger adults and females with the modified, high-potency live attenuated VZV vaccine may be warranted.

A phase 1 study of 4 live, recombinant human cytomegalovirus Towne/Toledo chimeric vaccines.

BACKGROUND: Human cytomegalovirus (HCMV) infection acquired in utero often results in severe consequences, including mental retardation and deafness. Although not evaluated for this indication, live attenuated HCMV vaccines based on the Towne strain are well-tolerated and have demonstrated moderate efficacy in other clinical settings. METHODS: To produce live HCMV vaccine candidates that retain the excellent safety profile of the Towne strain but are more immunogenic, the genomes of the Towne strain and the unattenuated HCMV Toledo strain were recombined to yield 4 independent chimeric vaccine candidates. These vaccine candidates were evaluated in 20 HCMV-seropositive persons, in a phase 1, double-blinded, placebo-controlled trial. Participants received a single dose of vaccine or placebo, and the safety and tolerability of the vaccine candidates were evaluated. RESULTS: There was no difference in systemic symptoms between the vaccine and placebo recipients. As a group, vaccine recipients experienced more injection-site reactions than did placebo recipients; however, these were generally minor and short-lived. Vaccine virus could not be detected in blood, urine, or saliva samples obtained from any vaccine recipient. CONCLUSIONS: The Towne/Toledo chimeric vaccine candidates were well tolerated and did not cause systemic infection. Additional human trials are warranted to further evaluate the potential of these vaccine candidates as live virus vaccines.

A comparison of haemagglutination, haemagglutination inhibition and PCR for the detection of psittacine beak and feather disease virus infection and a comparison of isolates obtained from loriids.

Psittacine beak and feather disease (PBFD) is recognized as a threat for endangered psittacine birds in Australia, New Zealand and South Africa. Several diagnostic methods for the detection of beak and feather disease virus (BFDV) infection have been developed but there are few studies comparing the relative merits or sensitivity and specificity of each diagnostic test. In this report, the results of PCR, haemagglutination (HA) and haemagglutination inhibition (HI) testing of diagnostic samples collected from 679 samples from a range of psittacine bird species suspected of being infected with BFDV are summarized and compared. There was a strong agreement (kappa = 0.757; P<0.0001) between PCR and HA testing of feather samples and PCR-negative birds were 12.7 times more likely to have HI antibody than PCR-positive birds. False-positive HA results with titres up to 1:320 were identified in six feather samples that were PCR negative; the haemagglutination detected in these samples was not inhibited by anti-BFDV antisera and was removed by filtration through a 0.22 microm filter. Similarly, one false-negative PCR result was detected in a feather sample that had a high HA titre (>1:40,960) and four false-positive PCR results were detected in a batch of four feather samples. Of 143 birds that were feather PCR positive, only two had detectable HI antibody, and these birds were also feather HA negative, suggesting that they were developing immunity to recent infection. All birds with HI antibody were negative on feather HA testing. The assays confirmed BFDV infection in two endangered swift parrots (Lathamus discolor) and phylogenetic analysis of the sequence data generated from ORF V1 of these isolates provide further evidence of BFDV genotypes clustering in parallel with the Loriidae, Cacatuidae and Psittacidae.

Antiviral CD8 T cells in the control of primary human cytomegalovirus infection in early childhood.

Human cytomegalovirus (CMV) establishes persistent infection, with control of replication thought to be mediated by CMV-specific CD8 T cells. Primary CMV infection commonly affects young children and causes prolonged viral shedding in saliva and urine. We investigated whether this virus-host interaction pattern reflects a developmental deficiency of antiviral CD8 T cell-mediated immunity during childhood. CMV-specific CD8 T cell responses in asymptomatic children with active infection were not different from adults with recent or long-term infection in frequency and functional analyses. High urine CMV concentrations were detected, despite these CMV-specific CD8 T cell responses. We conclude that delayed resolution of primary CMV infection in young children is not caused by a deficient CMV-specific CD8 T cell response. Because these healthy children continue to have local CMV replication, we suggest that CD8 T cells may function primarily to prevent symptomatic, disseminated disease.

Persistent and selective deficiency of CD4+ T cell immunity to cytomegalovirus in immunocompetent young children.

Healthy young children who acquire CMV have prolonged viral shedding into the urine and saliva, but whether this is attributable to limitations in viral-specific immune responses has not been explored. In this study, we found that otherwise immunocompetent young children after recent primary CMV infection accumulated markedly fewer CMV-specific CD4(+) T cells that produced IFN-gamma than did adults. These differences in CD4(+) T cell function persisted for more than 1 year after viral acquisition, and did not apply to CMV-specific IFN-gamma production by CD8(+) T cells. The IFN-gamma-producing CD4(+) T cells of children or adults that were reactive with CMV Ags were mainly the CCR7(low) cell subset of memory (CD45R0(high)CD45RA(low)) cells. The decreased IFN-gamma response to CMV in children was selective, because their CCR7(low) memory CD4(+) T cells and those of adults produced similar levels of this cytokine after stimulation with staphylococcal enterotoxin B superantigen. CD4(+) T cells from children also had reduced CMV-specific IL-2 and CD154 (CD40 ligand) expression, suggesting an early blockade in the differentiation of viral-specific CD4(+) T cells. Following CMV acquisition, children, but not adults, persistently shed virus in urine, and this was observable for at least 29 mo postinfection. Thus, CD4(+) T cell-mediated immunity to CMV in humans is generated in an age-dependent manner, and may have a substantial role in controlling renal viral replication and urinary shedding.

Identification of CD8+ T cell epitopes in the immediate early 62 protein (IE62) of varicella-zoster virus, and evaluation of frequency of CD8+ T cell response to IE62, by use of IE62 peptides after varicella vaccination.

Varicella-zoster virus (VZV) causes varicella, establishes neuronal latency, and can reactivate, resulting in herpes zoster. VZV-specific T cells are important for controlling infection. VZV immediate early protein 62 (IE62) is recognized by cytotoxic T cells from immune individuals, but no CD8(+) T cell epitopes have been defined for any VZV protein. CD8(+) T cell frequencies were assessed by cytokine flow cytometry (CFC), by use of synthetic-peptide pools corresponding to the IE62 sequence. IE62 peptide-specific CD8(+) T cells were below the threshold of detection, by direct CFC of either whole blood or peripheral blood mononuclear cells (PBMCs). Activated CD8(+)CD69(+) T cells that produced interferon-gamma were detectable after in vitro restimulation of PBMCs, and restricted epitopes were identified for HLA-A*0201-positive subjects. Varicella vaccination of 3 VZV-immune subjects was associated with increases in IE62 peptide-specific CD8(+) T cells, a finding indicating that in vivo re-exposure boosts memory immunity to this important viral protein.

Memory cytotoxic T cell responses to viral tegument and regulatory proteins encoded by open reading frames 4, 10, 29, and 62 of varicella-zoster virus.

Cytotoxic T cell recognition of tegument and regulatory proteins encoded by open reading frames (ORFs) 4, 10, 29, and 62 of varicella-zoster virus (VZV) was evaluated using limiting dilution conditions to estimate the precursor frequencies of memory T cells specific for these proteins in immune subjects. Responder cell frequencies for ORFs 4, 10, and 62 gene products, which are virion tegument components and function as immediate early viral transactivating proteins, were equivalent. CTLp recognition of VZV proteins made in latently infected cells, which include ORF4 and ORF62 proteins, was not maintained preferentially when compared to ORF10 protein, which has not been shown to be expressed during latency. T cell recognition of ORF29 protein, the major DNA binding protein, which is expressed during replication but not incorporated into the virion tegument, was less common than responses to ORFs 4, 10, and 62 gene products. Older individuals had diminished numbers of memory CTLp that lysed autologous targets expressing IE62 protein; these responses were increased after immunization with live attenuated varicella vaccine to the range observed in younger adults. Adaptive immunity to VZV is characterized by a broad repertoire of memory CTL responses to proteins that comprise the virion tegument and regulate viral gene expression in infected cells.

Use of an inactivated varicella vaccine in recipients of hematopoietic-cell transplants.

BACKGROUND: The reactivation of varicella-zoster virus from latency causes zoster and is common among recipients of hematopoietic-cell transplants. METHODS: We randomly assigned patients who were scheduled to undergo autologous hematopoietic-cell transplantation for non-Hodgkin's or Hodgkin's lymphoma to receive varicella vaccine or no vaccine. Heat-inactivated, live attenuated varicella vaccine was given within 30 days before transplantation and 30, 60, and 90 days after transplantation. The patients were monitored for zoster and for immunity against varicella-zoster virus for 12 months. RESULTS: Of the 119 patients enrolled, 111 received a transplant. Zoster developed in 7 of 53 vaccinated patients (13 percent) and in 19 of 58 unvaccinated patients (33 percent) (P=0.01). After two patients in whom zoster developed before transplantation were excluded, the respective rates were 13 percent and 30 percent (P=0.02). In vitro CD4 T-cell proliferation in response to varicella-zoster virus (expressed as the mean stimulation index) was greater in patients who received the vaccine than in those who did not at 90 days, after three doses (P=0.04); at 120 days, after all four doses (P<0.001); at 6 months (P=0.004); and at 12 months (P=0.02). The risk of zoster was reduced for each unit increase in the stimulation index above 1.6; a stimulation index above 5.0 correlated with greater than 93 percent protection. Induration, erythema, or local pain at the injection site was observed in association with 10 percent of the doses. CONCLUSIONS: Inactivated varicella vaccine given before hematopoietic-cell transplantation and during the first 90 days thereafter reduces the risk of zoster. The protection correlates with reconstitution of CD4 T-cell immunity against varicella-zoster virus.