Toll-like receptor 7 and 8 polymorphisms: associations with functional effects and cellular and antibody responses to measles virus and vaccine

Successful defence against viral pathogens requires the rapid recognition of virus-specific “danger signals” and the activation of both innate and adaptive immunity. Toll-like receptors (TLR) 7 and 8 play a critical role in the elimination of viruses by recognising the common viral component, single stranded (ss)RNA. Measles virus, an ssRNA virus, continues to cause serious morbidity and mortality worldwide despite available measles vaccines. TLR7 and TLR8 genetic variation may cause functional alterations that result in impaired responses to measles. In a population of 12-month-old Australian infants, receptor protein expression was examined to assess the functionality of TLR7 and TLR8 polymorphisms, and the effects of these polymorphisms on cellular and antibody responses after the first measles vaccine dose were investigated. TLR7 Leu11Gln showed associations with TNF-α responses after ligand (imiquimod) stimulation in males only (P = 0.040), and non-responders were more likely to be Gln males (P = 0.044). TNF-α non-responders after imiquimod also had higher percentages of TLR8 -4284TT (69.6%) (P = 0.001) and TLR8 -558CC (69.6%) (P = 0.002) in females. Receptor protein expression after imiquimod or measles stimulation was not significantly altered compared with baseline, nor was it affected by genotype. None of the TLR7 or TLR8 polymorphisms studied were associated with measles-specific cytokine levels or with measles IgG levels. In conclusion, we report gender-specific associations with TLR7 and TLR8 polymorphisms and TNF-α cellular responses to its ligand. However, we found no evidence of any functional effects of TLR7 or TLR8 polymorphisms on receptor expression, measles-specific cellular responses or measles vaccine antibody responses.     

Functional maturation of CD4+CD25+CTLA4+CD45RA+ T regulatory cells in human neonatal T cell responses to environmental antigens/allergens

A number of laboratories have reported cord blood T cell responses to ubiquitous environmental Ags, including allergens, by proliferation and cytokine secretion. Moreover, the magnitude of these responses has been linked with risk for subsequent expression of allergy. These findings have been widely interpreted as evidence for transplacental priming and the development of fetal T memory cells against Ags present in the maternal environment. However, we present findings below that suggest that neonatal T cell responses to allergens (and other Ags) differ markedly from those occurring in later life. Notably, in contrast to allergen-responsive adult CD4(+) T cell cultures, responding neonatal T cell cultures display high levels of apoptosis. Comparable responses were observed against a range of microbial Ags and against a parasite Ag absent from the local environment, but not against autoantigen. A notable finding was the appearance in these cultures of CD4(+)CD25(+)CTLA4(+) T cells that de novo develop MLR-suppressive activity. These cells moreover expressed CD45RA and CD38, hallmarks of recent thymic emigrants. CFSE-labeling studies indicate that the CD4(+)CD25(+) cells observed at the end of the culture period were present in the day 0 starting populations, but they were not suppressive in MLR responses. Collectively, these findings suggest that a significant component of the reactivity of human neonatal CD4(+) T cells toward nominal Ag (allergen) represents a default response by recent thymic emigrants, providing an initial burst of short-lived cellular immunity in the absence of conventional T cell memory, which is limited in intensity and duration via the parallel activation of regulatory T cells.     

Isolation of pl 4.6 extensin peroxidase from tomato cell suspension cultures and identification of Val—Tyr—Lys as putative intermolecular cross-link site

Extensins and kindred hydroxyproline-rich glycoproteins occur in dicot cell walls mainly as insoluble integral components that may form an intermolecularly cross-linked network interpenetrated by other polymers. Extensins also occur in muro as a small pool of soluble monomeric precursors to network extensin. These precursors were prepared in milligram quantities by salt elution from the surface of intact cells grown as tomato suspension cultures. Based on an FPLC (Superose-6) gel filtration assay of cross-linked extensin oligomers, a pl 4.6 extensin cross-linking peroxidase isozyme was partially purified from the culture growth medium. Purification involved: volume reduction, ultracentrifugation to remove pectin and co-adsorbed cationic peroxidase, followed by chromatography of anionic extensin peroxidase (pl 4.6) on DEAE—Trisacryl and TSK-gel DEAE-5PW columns. With tomato P1 extensin as substrate and 60 µM H₂O₂ as co-substrate, at 23° pl 4.6 extensin peroxidase gave a K,m of 0.22 mM P1 and a V _max of 70 µmol P1 cross-linked min⁻¹ mg⁻¹ enzyme, at the optimum pH 5.5. Assayed with 12 different extensins from representative monocots, dicots, and gymnosperms, the pl 4.6 isozyme cross-linked highly selectively, indicating two natural groups: cross-linking or CL-extensins and non-cross-linking or NCL-extensins. CL-extensins contained the X—Hyp—Val—Tyr—Lys motif and were also highly glycosylated. However, the simplest motif common to CL-extensins but absent from NCL-extensins was Val—Tyr—Lys. Thus, peroxidative coupling of extensin monomers and resistance of the resultant oligomers to depolymerization by anhydrous HF suggests that the intermolecular cross-link involves tyrosine or lysine.     

Three new ground wētā species and a redescription of Hemiandrus maculifrons

Taxonomy lies at the heart of species conservation, yet many large New Zealand orthopterans remain undescribed. Among New Zealand’s anostostomatid wētā, Hemiandrus (ground wētā) is the most speciose genus but also the most poorly characterised and thus most in need of taxonomic and ecological work. Here we redescribe H. maculifrons and describe two new species of ground wētā previously encompassed by the specific name Hemiandrus maculifrons: Hemiandrus luna sp. nov. and H. brucei sp. nov. We also describe a morphologically similar and related species, Hemiandrus nox sp. nov.

http://zoobank.org/urn:lsid:zoobank.org:pub:71EA0879-A2F9-46B2-A105-E97A9AB25061

http://zoobank.org/References/71EA0879-A2F9-46B2-A105-E97A9AB25061     

Tracing the diversification history of a Neogene rodent invasion into South America

We investigated spatial patterns of evolutionary relatedness and diversification rates to test hypotheses about the historical biogeographic processes underlying the radiation of Neotropical rats and mice (Sigmodontinae, ~400 species). A negative correlation between mean phylogenetic distance and diversification rates of rodent assemblages reveals a pattern of species co‐occurrence in which assemblages of closely related species are also the fastest diversifying ones. Subregions of the Neotropics occupied by distantly related species that are on average more slowly diversifying include Central America, northern South America, and the Atlantic forest. In southern South America, recent species turnover appears to have been higher. Ancestral locations for the main tribes of sigmodontines were also estimated, suggesting eastern South America and the Amazonian lowlands were colonized before some central Andean regions, even though the latter are now centers of species richness for these rodents. Moreover, a past connection between the tropical Andes and the Atlantic Forest is suggested by our results, highlighting a role for a hypothetical arc connecting the two biomes, which would have impacted many other groups of organisms. Whether rapid, recent speciation in some regions is related to Quaternary climatic fluctuations and the young age of sigmodontines (~12.7 Ma crown age) or instead to intrinsic traits of these rodents remains an open question. If the former is true, we hypothesize that contrasting trends will characterize older Neotropical clades.     

A modified and automated version of the 'Fluorimetric Detection of Alkaline DNA Unwinding' method to quantify formation and repair of DNA strand breaks

Background  

Formation and repair of DNA single-strand breaks are important parameters in the assessment of DNA damage and repair occurring in live cells. The 'Fluorimetric Detection of Alkaline DNA Unwinding (FADU)' method [Birnboim HC, Jevcak JJ. Cancer Res (1981) 41:1889–1892] is a sensitive procedure to quantify DNA strand breaks, yet it is very tedious to perform.     

Assessment of DNA damage and its modulation by dietary and genetic factors in smokers using the Comet assay: a biomarker model

Methods are needed to assess exposure to genotoxins in humans and to improve understanding of dietary cancer prevention. The Comet assay was used to detect smoking-related exposures and dietary modulations in target tissues. Buccal scrapings, blood and faeces were collected from 38 healthy male volunteers (smokers and non-smokers) during a dietary intervention study with bread supplemented with prebiotics±antioxidants. GSTM1-genotype was determined with PCR. Buccal and peripheral lymphocytes were analysed for DNA damage using the Comet assay. Genotoxicity of faecal water (FW) was assayed in human colon HT29 clone 19A cells. 'Tail intensity' (TI) was used as a quantitative indicator of DNA damage in the Comet assay. Intervention with bread reduced DNA damage in lymphocytes of smokers (8.3±1.7% TI versus 10.2±4.1% TI, n=19), but not of non-smokers (8.6±2.8% TI versus 8.3±2.7% TI, n=15). Faecal water genotoxicity was reduced only in non-smokers (9.4±2.9% TI versus 18.9±13.1% TI, n=15) but not in smokers (15.5±10.7% TI versus 20.4±14.1% TI, n=13). The Comet assay was efficient in the detection of both smoking-related exposure (buccal cells) and efficacy of dietary intervention (faecal samples). Smokers and non-smokers profited differently from the intervention with prebiotic bread±antioxidants. Stratification of data by genotype enhanced specificity/sensitivity of the intervention effects and contributed important information on the role of susceptibility.     

Influenza Vaccine Effectiveness against Hospitalisation with Confirmed Influenza in the 2010–11 Seasons: A Test-negative Observational Study

Immunisation programs are designed to reduce serious morbidity and mortality from influenza, but most evidence supporting the effectiveness of this intervention has focused on disease in the community or in primary care settings. We aimed to examine the effectiveness of influenza vaccination against hospitalisation with confirmed influenza. We compared influenza vaccination status in patients hospitalised with PCR-confirmed influenza with patients hospitalised with influenza-negative respiratory infections in an Australian sentinel surveillance system. Vaccine effectiveness was estimated from the odds ratio of vaccination in cases and controls. We performed both simple multivariate regression and a stratified analysis based on propensity score of vaccination. Vaccination status was ascertained in 333 of 598 patients with confirmed influenza and 785 of 1384 test-negative patients. Overall estimated crude vaccine effectiveness was 57% (41%, 68%). After adjusting for age, chronic comorbidities and pregnancy status, the estimated vaccine effectiveness was 37% (95% CI: 12%, 55%). In an analysis accounting for a propensity score for vaccination, the estimated vaccine effectiveness was 48.3% (95% CI: 30.0, 61.8%). Influenza vaccination was moderately protective against hospitalisation with influenza in the 2010 and 2011 seasons.