Publicação
Incorporation of Candida albicans cell wall surface proteins into lipid vesicles : physicochemical characterization and in vitro cytotoxicity
| Resumo: | Over the past two decades, Candida species have become the fourth most common cause of bloodstream infections with mortality rates higher than 50%. A significant improvement has been made in chemotherapy for candidiasis with the availability of new azole derivatives and inhibitors of glucan synthase. However, the mortality rate for invasive candidiasis has remained stable. These observations underline the urgent need for the development of novel approaches to fight fungal infections. Candida albicans cell wall has in its composition cell wall surface proteins (CWSPs), which are important targets for the host immune system. Therefore, the present study was developed in order to compare two distinct lipid systems, one constituted by phosphatidylethanolamine (PE) and another composed by DODAB:MO, regarding their ability to incorporate antigenic CWSPs for a future development of a safe and effective vaccine against C. albicans. After the successful incorporation of the CWSPs into lipid vesicles three characteristics were analyzed: average size of the lipid-CWSPs vesicles, their polydispersity index (PDI) and incorporation efficiency (IE). The PE-CWSPs vesicles presented average sizes between 268.9 nm and 492.4 nm and PDI values around 0.6. The MO, a neutral lipid, was included in the PE vesicles and the average size increased to 625.3 nm with PDI values of 0.5. DODAB:MOCWSPs vesicles average size ranged between 250.9 nm to 732.5 nm and the PDI values were considerably lower, around 0.3 to 0.5. After optimization of the delipidation method IE was determined and PE-CWSPs presented values ranging from 16.5% to 42.3%, whether PE:MOCWSPs vesicles presented lower values, around 25%. The DODAB:MO-CWSPs vesicles presented higher IE values, between 44.4% and 50,5%. Three formulations, PE (0.6mM)- CWSPs, DODAB:MO (0.1mM)-CWSPs and DODAB:MO (0.3mM)-CWSPs were chosen, from a total of eight, according to its size, PDI value and incorporation efficiency, to be tested for in vitro cytotoxicity and no significant cytotoxicity was observed. With the information collected in this work both systems, PE-CWSPs and DODAB:MOCWSPs, were considered to be suitable for the development of a vaccine against C. albicans infections. |
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| Autores principais: | Vaz, Catarina Oliveira |
| Ano: | 2012 |
| País: | Portugal |
| Tipo de documento: | dissertação de mestrado |
| Tipo de acesso: | acesso aberto |
| Instituição associada: | Universidade do Minho |
| Idioma: | inglês |
| Origem: | RepositóriUM - Universidade do Minho |
| Resumo: | Over the past two decades, Candida species have become the fourth most common cause of bloodstream infections with mortality rates higher than 50%. A significant improvement has been made in chemotherapy for candidiasis with the availability of new azole derivatives and inhibitors of glucan synthase. However, the mortality rate for invasive candidiasis has remained stable. These observations underline the urgent need for the development of novel approaches to fight fungal infections. Candida albicans cell wall has in its composition cell wall surface proteins (CWSPs), which are important targets for the host immune system. Therefore, the present study was developed in order to compare two distinct lipid systems, one constituted by phosphatidylethanolamine (PE) and another composed by DODAB:MO, regarding their ability to incorporate antigenic CWSPs for a future development of a safe and effective vaccine against C. albicans. After the successful incorporation of the CWSPs into lipid vesicles three characteristics were analyzed: average size of the lipid-CWSPs vesicles, their polydispersity index (PDI) and incorporation efficiency (IE). The PE-CWSPs vesicles presented average sizes between 268.9 nm and 492.4 nm and PDI values around 0.6. The MO, a neutral lipid, was included in the PE vesicles and the average size increased to 625.3 nm with PDI values of 0.5. DODAB:MOCWSPs vesicles average size ranged between 250.9 nm to 732.5 nm and the PDI values were considerably lower, around 0.3 to 0.5. After optimization of the delipidation method IE was determined and PE-CWSPs presented values ranging from 16.5% to 42.3%, whether PE:MOCWSPs vesicles presented lower values, around 25%. The DODAB:MO-CWSPs vesicles presented higher IE values, between 44.4% and 50,5%. Three formulations, PE (0.6mM)- CWSPs, DODAB:MO (0.1mM)-CWSPs and DODAB:MO (0.3mM)-CWSPs were chosen, from a total of eight, according to its size, PDI value and incorporation efficiency, to be tested for in vitro cytotoxicity and no significant cytotoxicity was observed. With the information collected in this work both systems, PE-CWSPs and DODAB:MOCWSPs, were considered to be suitable for the development of a vaccine against C. albicans infections. |
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