Dendritic cells (DCs) due to their ability to present antigens are essential during the immune response to infections. The aim of the study was to evaluate the influence of bovine leukaemia virus (BLV) infection on DC properties. Cytokine profiles of myeloid, plasmacytoid and mono- cyte derived DCs from BLV infected cattle were analysed. Concentrations of IL-6, IL-10, IL-12, IFN-γ, and TNF-α in DC cultures were measured by flow cytometry. Obtained results indicated activation of pDCs population, where a significant increase in production of the IFN-γ was shown. Meanwhile, a decrease in production of IFN-γ and increase in production of IL-10 were shown in mDCs; the main population responsible for antigens presentation. This may indicate a contribu- tory role of the population during the process of persistent infection. In MoDCs population a significant elevation in secretion of proinflammatory cytokines – IL-6 and TNF-α was noted.
Telomeres are repetitive sequence structures at the ends of chromosomes. They consist of the double stranded DNA repeats followed by the short single stranded DNA. In humans and other verterbrates the telomeric sequence is composed of tandem of TTAGGG repeats. With each cells division telomeres shorten by up to 200 base pairs. Telomerase is an enzyme responsible for continuous cell growth and is repressed in most somatic cells, except proliferating progenitor cells, but in more than 85% of cancer cells telomerase expression is observed. Tumour cells with metastatic potential may demonstrate a high telomerase activity, allowing cells to escape from the inhibition of cell proliferation due to shortened telomeres. Determination of telomerase expres- sion was performed with the use of PCR ELISA in samples isolated from bovine leukaemia virus (BLV) infected cows. Telomerase activity was found in almost all investigated samples. The relative telomerase activity (RTA) was higher in infected cows than in healthy animals and the differences were statistically significant (α=0.05). In blood lymphocytes of BLV-infected cows the mean values of telomerase expression determined in real-time PCR were 3534.12 copies, in the healthy group there were 1010.10 copies and these differences were also statistically significant. For telomere length evaluation the Telomere PNA/FITC FISH and Telomere PNA/FITC FISH for flow cytometry were used. The mean fluorescence intensity of telomere sequences calculated on the surface of interphase nuclei of leukaemic blood lymphocytes was lower than that in the control animals and the difference was statistically significant. The mean length of telomeres in BLV- infected and healthy cows was 31.63 ± 12.62 and 38.4 ± 4.03, (p=0.112), respectively.
SI engines are highly susceptible to excess emissions when started at low ambient temperatures. This phenomenon has multiple air quality and climate forcing implications. Direct injection petrol engines feature a markedly different fuelling strategy, and so their emissions behaviour is somewhat different from indirect injection petrol engines. The excess emissions of direct injection engines at low ambient temperatures should also differ. Additionally, the direct injection fuel delivery process leads to the formation of PM, and DISI engines should show greater PM emissions at low ambient temperatures. This study reports on laboratory experiments quantifying excess emissions of gaseous and solid pollutants over a legislative driving cycle following cold start at a low ambient temperature for both engine types. Over the legislative cycle for testing at -7°C (the UDC), emissions of HC, CO, NOx and CO2 were higher when tested at -7°C than at 24°C. Massive increases in emissions of HC and CO were observed, together with more modest increases in NOx and CO2 emissions. Results from the entire driving cycle showed excess emissions in both phases (though they were much larger for the UDC). The DISI vehicle showed lower increases in fuel consumption than the port injected vehicles, but greater increases in emission of HC and CO. DISI particle number emissions increased by around 50%; DISI particle mass by over 600%. The observed emissions deteriorations varied somewhat by engine type and from vehicle to vehicle. Excesses were greatest following start-up, but persisted, even after several hundred seconds’ driving. The temperature of the intake air appeared to have a limited but signiﬁcant effect on emissions after the engine has been running for some time. All vehicles tested here comfortably met the relevant EU limits, providing further evidence that these limits are no longer challenging and need updating.