Large-scale cultivation of Leishmania infantum promastigotes in stirred bioreactor.

BACKGROUND & OBJECTIVES: Bioreactors are practical tools that are used for economical, time-conserving and large-scale production of biomass from cell cultivation. They provide optimal environmental conditions such as pH and temperature required for obtaining maximum amounts of biomass. However, there is no evidence in the literature on the large-scale cultivation of Leishmania infantum parasites in the bioreactor. Therefore, the present study was undertaken to develop a new approach for obtaining L. infantum biomass by using pH and temperature controllable stirred bioreactor and to compare parasitic growth kinetics with classical method within erlenmeyers. METHODS: In order to obtain parasite biomass, a newly developed pH and temperature controlled stirred bioreactor was used and its efficacy was compared with a graduated classical scale-up method. Growth kinetics of parasites within erlenmeyers and bioreactors were determined by evaluating promastigote numbers using haemocytometer. The graduated scale enlargement of culture was followed by T25 flask, T75 flask, and 1 L erlenmeyer, respectively. RESULTS: Obtained results showed a 10-fold increase in the number of promastigotes within the conventional culture performed in 700 ml medium, while parasite numbers increased approximately 15 times due to initial inoculation amounts in the bioreactor culture performed in the 3.5 l medium. Thus, there was 7.5 times more biomass collection in bioreactor compared to classical method. INTERPRETATION & CONCLUSION: It is postulated that constant culture pH and temperature in the bioreactor extends cultivation time. This could lead to significant increase in parasite numbers. Hence, pH and temperature controllable bioreactors provided acquisition of sufficient amounts of biomass in contrast to classical methods. Therefore, this type of bioreactors may substitute classical culture methods in the production of antigenic molecules for vaccine development.

An overview of challenges to eradication of Helicobacter pylori infection and future prospects.

The eradication of H. pylori infection continues to be a challenge due to the evolution of drug-resistant bacteria, lack of a gold standard diagnostic method, and ineffectiveness of current vaccines. Additionally, there still is no consensus in the literature about the main source of gastric H. pylori infection. The bacterium has also been demonstrated to colonize in dental plaque and the oral cavity. We believe that to develop new approaches for successful eradication of the disease, factors such as the biology of the bacterium, reservoir differentiations, host-bacterium interactions and problems in diagnosis, treatment and vaccination must be comprehensively considered. Therefore, the main goal of this study is to gather all of the literature analysis about the problems in the eradication of the infection, reconsider contradictions about extra-gastric reservoirs of the bacterium, and propose new strategies aimed at disease eradication.

Overview of dendritic cell-based vaccine development for leishmaniasis.

Leishmaniasis is one of the most serious vector-borne diseases in the world and is distributed over 98 countries. It is estimated that 350 million people are at risk for leishmaniasis. There are three different generation of vaccines that have been developed to provide immunity and protection against leishmaniasis. However, their use has been limited due to undesired side effects. These vaccines have also failed to provide effective and reliable protection and, as such, currently, there is no safe and effective vaccine for leishmaniasis. Dendritic cells (DCs) are a unique population of cells that come from bone marrow and become specialized to take up, process and present antigens to helper T cells in a mechanism similar to macrophages. By considering these significant features, DCs stimulated with different kinds of Leishmania antigens have been used in recent vaccine studies for leishmaniasis with promising results so far. In this review, we aim to review and combine the latest studies about this issue after defining potential problems in vaccine development for leishmaniasis and considering the importance of DCs in the immunopathogenesis of the disease.