Liposome-based subunit and DNA hepatitis B vaccines

It has been shown that liposomes have immunological adjuvant properties and earlier evidence suggested that liposomes could play a role in vaccination against hepatitis B. The objective of this thesis is to optimize the liposomal formulations for hepatitis B vaccines and to investigate the effect of these formulations on antibody induction by hepatitis B surface antigen (HBsAg). In the present studies, the work on liposomes as a carrier for a hepatitis B vaccine was carried out and promising formulations were selected for further research. The HBsAg and plasmid pRc/CMV HBS DNA were entrapped into liposomes and these formulations were evaluated in terms of preparation procedures, characteristics, stability upon storage and in vitro release behaviours. Recombinant HBsAg and a plasmid DNA (pRc/CMV HBS) encoding for HBsAg (S region) were entrapped into liposomes by the dehydration-rehydration method yielding dehydration-rehydration vesicles (DRV). The effect of lipid composition, vesicle size, protein characteristics, routes of administration and direct or indirect immunisation were studied. To investigate the adjuvant effect of liposomes, the mice were immunised with a variety of formulations. HBsAg-containing DRVs composed of DSPC/Chol (1:1 molar ratio) elicited stronger IgG responses in mice than liposomes composed of PC/Chol (1:1 molar ratio). Furthermore, microfluidised HBsAg-containing DRVs (smaller vesicle size) did not influence the IgG responses. However, HBsAg-containing DRVs prepared in the presence of sucrose, which have a similar size to microfluidised DRVs, were found to enhance the IgG responses to HBsAg. In addition, mannosylated HBsAg changes the adjuvant effect of liposomes. Cholesterol- containing DRVs did not enhance the IgG responses to mannosylated HBsAg, but DSPC/DOPE DRVs induced stronger IgG responses in mice immunized with mannosylated HBsAg. There was improvement of immunological adjuvant properties of liposomes by the oral route by conjugating cholera toxin B (CTB) to HBsAg-containing DRVs. Furthermore, a novel method was produced to prepare the liposomal formulations of DNA by entrapping calcium phosphate-DNA complexes into the liposomes (capisomes). Capisomes incorporating pRc/CMV HBS plasmid were evaluated in mice in terms of humoral immunity to the encoding antigen. From these studies, liposomes were shown to be versatile as immunological adjuvants for protein or DNA vaccines, or as a carrier for a combination of the two types of vaccines to develop single-dose vaccines against hepatitis B. HBsAg-containing DRVs prepared in the presence of sucrose can enhance the antibody responses to HBsAg. CTB-conjugated DRVs provide an opportunity to deliver antigen orally and capisomes offer another delivery system for DNA vaccination against hepatitis B. Further studies for these formulations are recommended

Does Long-Term Use of Silver Nanoparticles Have Persistent Inhibitory Effect on H. pylori Based on Mongolian Gerbil’s Model?

It is urgent to find alternative agents due to increasing failure rate of Helicobacter pylori (H. pylori) eradication. The study surveyed the long-term effect of silver nanoparticles (AgNP) on H. pylori based on Mongolian gerbil's model

Impaired dendritic cell maturation and IL-10 production following H. pylori stimulation in gastric cancer patients

The current study was to investigate the interaction between Helicobacter pylori and human dendritic cells (DCs). Whether impaired DC function can influence the outcome of H. pylori infections. Human monocyte-derived DCs (MDDCs) from five gastric cancer patients and nine healthy controls were stimulated with H. pylori. Maturation markers of MDDC were examined by flow cytometry. IL-10 and TNF-α released by MDDCs and IL-17 produced by T cells were measured by ELISA. Regulatory signaling pathways of IL-10 were examined by ELISA, western blotting, and chromatin immunoprecipitation assay. The results showed that as compared with healthy individuals, the maturation marker CD40 in MDDCs, IL-17A expression from T cells, and IL-10 expression from MDDCs were significantly lower in gastric cancer patients. Blocking DC-SIGN, TLR2, and TLR4 could reverse H. pylori-associated IL-10 production. Activation of the p38 MAPK and NF-kB signaling pathways concomitant with decreased tri-methylated H3K9 and increased acetylated H3 accounted for the effect of H. pylori on IL-10 expression. Furthermore, upregulated IL-10 expression was significantly suppressed in H. pylori-pulsed MDDCs by histone acetyltransferase and methyltransferase inhibitors. Taken together, impaired DC function contributes to the less effective innate and adaptive immune responses against H. pylori seen in gastric cancer patients. H. pylori can regulate IL-10 production through Toll-like and DC-SIGN receptors, activates p-p38 MAPK signaling and the transcription factors NF-kB, and modulates histone modification

Investigation of Anthelmintic Property of Cow Urine Distillate on Ascaris and Trichuris eggs Isolated from Soil

Background: Helminth infection occurs due to contact with contaminated soils and poor hygiene practices. Even though there is immense progression in human medicine, infections that occur due to bacteria, fungi, viruses, and parasites persist as a crucial threat to public health. Over the years, many studies indicated cow urine has antimicrobial activity. Hence, this study looks into anthelminthic property of cow urine in Ascaris spp., and Trichuris spp., eggs. Methods: The soil sample was collected at the riverside, near the toilet area and at the pond area at an aborigine village in Malaysia. Next, floatation technique was used to isolate the helminth eggs and it was identified using a light microscope. The cow urine was prepared as raw cow urine (RCU), evaporated raw cow urine diluted with distilled water (ERCUD), evaporation raw cow urine diluted with saline (ERCUS) and evaporated filtered cow urine diluted with saline (EFCUS).Results: From the soil samples, mainly two types of helminths were found which were Ascaris lumbricoides and Trichuris trichiura. Evaporated cow urine diluted with saline showed the most prominent result in the destruction of helminth eggs.Conclusion: Evaporated cow urine possesses biochemical agents that can be used in the future as anthelmintic agents whereby further studies can be made to explore more possibilities to use cow urine as a potential anthelmintic agent.Keywords: Cow urine; Helminth eggs; Anthelmintic 

Experimental investigation of woody and non-woody biomass combustion in a bubbling fluidised bed combustor focusing on gaseous emissions and temperature profiles

Air staging is a well-known effective method to control NOx emissions from solid fuel combustion boilers. However, further research is still needed to clarify the effect of air staging at different injection locations on the gaseous emissions of Fluidised Bed Combustion (FBC) boilers that fire 100% biomass fuels, particularly non-woody biomass fuels. The main objective of this work is to investigate the effect of the staging air injection location on the gaseous emissions (NOx and CO) and temperature profiles of a 20 kWth bubbling fluidised bed combustor firing three non-woody (straw, miscanthus and peanuts) and two woody biomass fuels. The experimental results showed that injecting the secondary air at the higher location could lead to a greater NOx reduction due to the fact that the biomass combustion reaction mainly took place in the splash zone and/or beginning of the freeboard. Up to 30% of NOx reduction, compared with no air staging, was achieved for the non-woody fuels when the staging air was injected at the higher position. Air staging also significantly reduced the CO emissions as a result of the higher temperatures in the freeboard and longer residence time in the primary combustion zone