Seroprevalence of HBV and HCV in primary hepatocellular carcinoma patients in Zimbabwe

BACKGROUND:Primary hepatocellular carcinoma (PHC) is one of the most common cancers in Zimbabwe. Hepatitis B virus (HBV) and hepatitis C virus (HCV) are suspected to play a major role in causing this cancer. The objective of this study was to determine the seroprevalence of HBV and HCV in PHC at Parirenyatwa Referral Hospital in Zimbabwe. We evaluated the serological markers of the two viruses in patients with PHC using commercially available enzyme-linked immunosorbent kits. RESULTS: Out of the 60 patients with PHC, 48.3% were seropositive for HBV and 20.0% were seropositive for HCV. Co-infection by HCV and HBV was found in 8% of the patients. Only 13.3% of the health controls (blood donors) were positive for HBV. All the controls were negative for HCV. CONCLUSION: The high seropositivity of HBV and HCV in PHC in Zimbabwe suggested that the two viruses were a major cause of the cancer

An oral recombinant Salmonella enterica serovar Typhimurium mutant elicits systemic antigen-specific CD8+ T cell cytokine responses in mice

<p>Abstract</p> <p>Background</p> <p>The induction of antigen-specific CD8+ T cell cytokine responses against an attenuated, oral recombinant <it>Salmonella enterica </it>serovar Typhimurium vaccine expressing a green fluorescent protein (GFP) model antigen was investigated. A GFP expression plasmid was constructed in which the <it>gfp </it>gene was fused in-frame with the 5' domain of the <it>Escherichia coli β</it>-galactosidase <it>α</it>-gene fragment with expression under the <it>lac </it>promoter. Groups of mice were orally immunized three times with the bacteria and systemic CD8+ T cell cytokine responses were evaluated.</p> <p>Results</p> <p>High level of the GFP model antigen was expressed by the recombinant <it>Salmonella </it>vaccine vector. Systemic GFP-specific CD8+ T cell cytokine (IFN-γ and IL-4) immune responses were detected after mice were orally vaccinated with the bacteria. It was shown that 226 net IFN-γ and 132 net IL-4 GFP-specific SFUs/10e6 splenocytes were formed in an ELISPOT assay. The level of IFN-γ produced by GFP peptide-stimulated cells was 65.2-fold above background (p < 0.05). The level of IL-4 produced by the cells was 10.4-fold above background (p < 0.05).</p> <p>Conclusion</p> <p>These results suggested that a high expressing recombinant <it>Salmonella </it>vaccine given orally to mice would elicit antigen-specific CD8+ T cell responses in the spleen. <it>Salmonella </it>bacteria may, therefore, be used as potential mucosal vaccine vectors.</p

Oral vaccination with a recombinant Salmonella vaccine vector provokes systemic HIV-1 subtype C Gag-specific CD4+ Th1 and Th2 cell immune responses in mice

<p>Abstract</p> <p>Background</p> <p>Recombinant <it>Salmonella </it>vaccine vectors may potentially be used to induce specific CD4+ T cell responses against foreign viral antigens. Such immune responses are required features of vaccines against pathogens such as human immunodeficiency virus type 1 (HIV-1). The aim of this study was to investigate the induction of systemic HIV-1-specific CD4+ T helper (Th) responses in mice after oral immunization with a live attenuated <it>Salmonella </it>vaccine vector that expressed HIV-1 subtype C Gag. Groups of BALB/c mice were vaccinated orally three times (4 weeks apart) with this recombinant <it>Salmonella</it>. At sacrifice, 28 days after the last immunization, systemic CD4+ Th1 and Th2 cytokine responses were evaluated by enzyme-linked immunospot assay and cytometric bead array. HIV-1 Gag-specific IgG1 and IgG2a humoral responses in the serum were determined by enzyme-linked immunosorbent assay.</p> <p>Results</p> <p>Mice vaccinated with the recombinant <it>Salmonella </it>elicited both HIV-1-specific Th1 (interferon-gamma (IFN-γ) and tumour necrosis factor-alpha (TNF-α)) and Th2 (interleukin-4 (IL-4) and interleukin-5 (IL-5)) cytokine responses. The vaccine induced 70 (IFN-γ) spot-forming units (SFUs)/10e6 splenocytes and 238 IL-4 SFUs/10e6 splenocytes. Splenocytes from vaccinated mice also produced high levels of Th1 and Th2 cytokines upon stimulation with a Gag CD4 peptide. The levels of IFN-γ, TNF-α, IL-4 and IL-5 were 7.5-, 29.1-, 26.2- and 89.3-fold above the background, respectively. Both HIV-1 Gag-specific IgG1 and IgG2a antibodies were detected in the sera of vaccinated mice.</p> <p>Conclusion</p> <p>The study highlights the potential of orally-delivered attenuated <it>Salmonella </it>as mucosal vaccine vectors for HIV-1 Subtype C Gag to induce Gag-specific CD4+ Th1 and Th2 cellular immune responses and antibodies which may be important characteristics required for protection against HIV-1 infection.</p

Salmonella typhimurium and Escherichia coli dissimilarity: closely related bacteria with distinct metabolic profiles

Live attenuated strains of Salmonella typhimurium have been extensively investigated as vaccines for a number of infectious diseases. However, there is still little information available concerning aspects of their metabolism. S. typhimurium and Escherichia coli show a high degree of similarity in terms of their genome contents and metabolic networks. However, this work presents experimental evidence showing that significant differences exist in their abilities to direct carbon fluxes to biomass and energy production. It is important to study the metabolism of Salmonella in order to elucidate the formation of acetate and other metabolites involved in optimizing the production of biomass, essential for the development of recombinant vaccines. The metabolism of Salmonella under aerobic conditions was assessed using continuous cultures performed at dilution rates ranging from 0.1 to 0.67 h1, with glucose as main substrate. Acetate assimilation and glucose metabolism under anaerobic conditions were also investigated using batch cultures. Chemostat cultivations showed deviation of carbon towards acetate formation, starting at dilution rates above 0.1 h1. This differed from previous findings for E. coli, where acetate accumulation was only detected at dilution rates exceeding 0.4 h1, and was due to the lower rate of acetate assimilation by S. typhimurium under aerobic conditions. Under anaerobic conditions, both microorganisms mainly produced ethanol, acetate, and formate. A genome-scale metabolic model, reconstructed for Salmonella based on an E. coli model, provided a poor description of the mixed fermentation pattern observed during Salmonella cultures, reinforcing the different patterns of carbon utilization exhibited by these closely related bacteria. This article is protected by copyright. All rights reserved.Special thanks to Amadeus Azevedo for the HPLC analyses and technical assistance. The authors acknowledge the national funding received from CNPq (Conselho Nacional de Desenvolvimento Cientifico e Tecnologico, Brazil), the international cooperation project CAPES-FCT (Coordenacao de Aperfeicoamento de Pessoal de Nivel Superior/Brazil-Fundacao para a Ciencia e a Tecnologia/Portugal-Process 315/11), CAPES (Atracao de Jovens Talentos-Process 064922/2014-01) and to Fundacao para a Ciencia e Tecnologia the strategic funding of UID/BIO/04469/2013 unit

The use of directed evolution to create a stable and immunogenic recombinant BCG expressing a modified HIV-1 Gag antigen

Numerous features make Mycobacterium bovis BCG an attractive vaccine vector for HIV. It has a good safety profile, it elicits long-lasting cellular immune responses and in addition manufacturing costs are affordable. Despite these advantages it is often difficult to express viral antigens in BCG, which results in genetic instability and low immunogenicity. The aim of this study was to generate stable recombinant BCG (rBCG) that express high levels of HIV antigens, by modification of the HIV genes. A directed evolution process was applied to recombinant mycobacteria that expressed HIV-1 Gag fused to the green fluorescent protein (GFP). Higher growth rates and increased GFP expression were selected for. Through this process a modified Gag antigen was selected. Recombinant BCG that expressed the modified Gag (BCG[pWB106] and BCG[pWB206]) were more stable, produced higher levels of antigen and grew faster than those that expressed the unmodified Gag (BCG[pWB105]). The recombinant BCG that expressed the modified HIV-1 Gag induced 2 to 3 fold higher levels of Gag-specific CD4 T cells than those expressing the unmodified Gag (BCG[pWB105]). Mice primed with 10 7 CFU BCG[pWB206] and then boosted with MVA-Gag developed Gag-specific CD8 T cells with a frequency of 1343±17 SFU/10 6 splenocytes, 16 fold greater than the response induced with MVA-Gag alone. Levels of Gag-specific CD4 T cells were approximately 5 fold higher in mice primed with BCG[pWB206] and boosted with MVA-Gag than in those receiving the MVA-Gag boost alone. In addition mice vaccinated with BCG[pWB206] were protected from a surrogate vaccinia virus challenge

Recombinant Salmonella enterica Serovar Typhimurium as a Vaccine Vector for HIV-1 Gag

The HIV/AIDS epidemic remains a global health problem, especially in Sub-Saharan Africa. An effective HIV-1 vaccine is therefore badly required to mitigate this ever-expanding problem. Since HIV-1 infects its host through the mucosal surface, a vaccine for the virus needs to trigger mucosal as well as systemic immune responses. Oral, attenuated recombinant Salmonella vaccines offer this potential of delivering HIV-1 antigens to both the mucosal and systemic compartments of the immune system. So far, a number of pre-clinical studies have been performed, in which HIV-1 Gag, a highly conserved viral antigen possessing both T- and B-cell epitopes, was successfully delivered by recombinant Salmonella vaccines and, in most cases, induced HIV-specific immune responses. In this review, the potential use of Salmonella enterica serovar Typhimurium as a live vaccine vector for HIV-1 Gag is explored

An analytical analysis of abortion laws in Zimbabwe from a human rights perspective

Abortion is an “unlawful and intentional killing and causing the expulsion from the uterus of a human foetus”. At the heart of the abortion debate exists’ those who affiliate with the pro-life debate which is based mainly on the status of the embryo. The pro-life debate maintains that life and personhood begin at conception hence the right to life applies at conception and no other considerations can nullify this right. It accords the foetus with the status of a person with rights and interests worthy of legal protection. Against this argument are those that maintain that the embryo is never a person and that a woman has a right to abortion at any point of the pregnancy. They state inter alia that forcing a woman to carry a foetus to term is an invasion of her bodily integrity, moral autonomy and her moral rights to be treated as a human being. Thus, abortion becomes a human rights issue because of the right of autonomy in decision making in private matters which entitles a woman to decide whether to carry the foetus to term without any interference from the governmen

Recombinant Salmonella enterica serovar Typhimurium vaccine vector expressing green fluorescent protein as a model antigen or human immunodeficiency virus type 1 subtype C Gag

Includes bibliographical references (leaves 172-200)