Peptide loaded nano vaccine formulation and in vivo examination of efficiency against toxoplasma gondii

Toxoplasma gondii is an intracellular mandatory parasite that can infect all of the warm blooded animals. Intermediate hosts of Toxoplasma gondii which is widespread all over the earth are all of the mammals including people and poulries, also it's last hosts are cats and Felidae. T.gondii infects all types of cells and it is one of the most important eucaryotic pathogens in medicine and veterinary medicine since it is a zootonic parasite which performs cell invasion actively. T. gondii can be found in three different infective forms throughout it's lifespan including tachyzoite, bradyzoite and sporozoite. The parasite consist of tachyzoites which are fast-growing forms of the parasite, bradyzoites which are located in tissue cysts and oocyst forms which are devoloping in intestine of cats the last hosts. All of these three forms can play role in infecting people and they can be primer and chronic infections, also they can cause to be morbidiy and mortality. Nowadays, there is only one vaccine which is named Toxovax is verified for using against Toxoplasma disease which is caused by T.gondii. Apart from that, there is no verified vaccine which can be used on people. Considering the effect of T. gondii on the world, the importance of developing an effective vaccine is intelligible. Although subunit vaccines which are commonly used in current vaccine trials have an important place, there are needs for carrier systems and adjuvant for effective using. The advantages of nanovaccines, which are a new vaccination applications emerging with the development of nanotechnology in recent years, are quite impressive compared to other vaccines. iv Nanovaccines have promising advantages such as the establishment of controlled release system in nano-scale formulation, the ease of transport, the protection of antigens etc. These advantages make nanovaccines highly attractive for using in nanomedicine field. Nowadays, nanostructured formulations are formed with Poly (Lactic-co-Gycolic Acid) PLGA which is approved as biocompatible and biodegradable by US Food and Drug Administration (FDA) and European Drug Agency. In this thesis study, it is aimed to investigate in vivo the efficacy of the nano vaccine formulation formed by the peptide sequence belonging to SAG1 which is an important surface antigen of Toxoplasma gondii parasite. The toxicity of peptide loaded PLGA vaccine formulations which were prepared by encapsulation was performed by XTT method with using mouse fibroblast cell line L929 cells. Afterwards in different combinations of formulations were generated in order to perform comparative examination. In this regard, it was studied with four different BALB/c mouse groups and each of them was injected with nano vaccine, peptide group, adjuvant peptide mixture and control group, respectively. After injection of serum samples immunoreactivity was determined by ELISA technique. In order to measure in vitro activity of macrophages, cell isolation was made from spleen and cytokine responses and measurements of lymphocyte preprophyation were performed.