Anti-PARVA monoclonal antibody, clone 4I3

East Coast fever (ECF) caused by Theileria parva kills cattle in East, Central and Southern Africa leading to significant economic losses. Vaccination is used as a control strategy against ECF and is presently dependent on deliberate infection with live sporozoites and simultaneous treatment with a long-acting oxytetracycline. Although effective, this method has serious limitations; the immunity is parasite strain specific and immunized cattle can become life-long asymptomatic carriers of the parasite, posing risk for the spread of the disease. In efforts to develop a subunit vaccine, the role of antibodies in the neutralization of T. parva sporozoites infection of host cells has been investigated and a circumsporozoite protein, p67, is able to induce such neutralizing antibodies. However, the p67 protein only protects a proportion of immunized cattle against T. parva challenge and such protection might be improved by inclusion of additional parasite antigens that neutralize sporozoite infection. In an attempt to identify such antigens, we searched the re-annotated T. parva genome for genes predicted to contain GPI anchor signals, since they are likely to be located on the cell surface, and expressed fragments of six of the selected genes in E. coli. The recombinant proteins were used to raise antisera in mice. Antisera to two proteins, TpMuguga_01g00876 and TpMuguga_01g00939, neutralized sporozoite infectivity to a high degree, while antisera to two additional proteins, TpMuguga_01g00095 and TpMuguga_04g00437, exhibited moderate neutralizing capacity. We conclude that these four antigens are potential vaccine candidates, which should be evaluated further in cattle.

The gas hydrate deposit in Shenhu, Northern South China Sea (NSCS) was one of the main sources for deep-water hydrocarbon and hydrate. Based on field observations on a gas hydrate deposit among 20 x 20 km(2) at Shenhu of the northern continental slope of SCS in May (before drilling) and September (after drilling) in 2015, environmental baseline, comparisons of phytoplankton community, biomass and potential environmental drivers were studied. Results indicated the deposit area was a typical low-nutrients low-chlorophyll a (LNLC) environment, characterized by low phytoplankton abundance and diversity. The maximum of abundance and Chl a were fixed at 75 m before and after drilling, but their decrease was larger from 0.53 mg/m(3) to 0.40 mg/m(3) and 1218 cells/L to 843 cells/L with non-significance found, respectively. After drilling, ammonium decreased significantly (2.13 mu mol/L to 0.20 mu mol/L), along with nitrite, salinity and dissolved methane, while pH increased significantly (8.10-8.19). Phytoplankton community was composed of 97 taxa of 47 genera in 4 classes, including diatoms, dinoflagellates, cyanobacteria and chrysophyte. The dominant diatom species before and after drilling remained the same, which included Navicula parva, Pseudonitzchia circumpora and Fragilariopsis doliolus. Dominant dinoflagellates shifted from the cosmopolitan Scrippsiella trochoidea to the warm-water adapted Gyrodinium flavum. The diazotrophic cyanobacterium Trichodesmium thiebaultii become more apparent in higher occurrence and abundance due to alleviation from lower-pH inhibition on nitrogen fixation. Redundancy analysis and Spearman correlation analysis revealed that the dominant species and Chl a were mainly associated to pH, DO and nitrite. The X-bar control chart indicated that a constrained maximum problem of phytoplankton abundance in particular layers (50 m, 75 m and 100 m). We clearly documented in the revisited stations (SH3-W2 and SH3-W14), the decrease of abundance and Chl a and the increase of pH and DO were evident in each sampling layer accompanied with lower dissolved methane associated to in situ anoxic or aerobic microniches activities, but the correlations with dissolved methane were not strong.