Protective efficacy of Toxoplasma gondii infected cells-derived exosomes against chronic murine toxoplasmosis.

Exosomes were isolated from T. gondii infected human hepatoblastoma cells using the exosome isolation kit and characterized by electron microscopy and Western blotting. Exosomes adsorbed to alum adjuvant were evaluated as a potential immunizing agent against murine chronic toxoplasmosis compared to excretory secretory antigens (ESA)-alum. Mice were immunized at days 1, 15 and 29. The levels of IgG, IFN-γ, IL-4 and IL-10, CD4+ and CD8+ T cells were determined using sandwich enzyme-linked immunosorbent assay (sandwich ELISA) at days 14, 28 and 56 of the experiment. Then mice were infected orally with 10 cysts of T. gondii. The protective efficacy of the antigens were evaluated by counting the brain cysts and measuring the aforementioned humoral and cellular parameters 60 days post infection. The results showed that alum increased the protective efficacy of the exosomes. Immunization with exosome-alum induced both humoral and mixed Th1/Th2 cellular immune responses. Exosome-alum gave higher levels of the humoral and cellular parameters, compared to ESA-alum. After challenge infection, exosome-alum significantly reduced the brain cyst burden by 75 % while ESA-alum gave 42 % reduction and evoked higher humoral and cellular immune responses. Therefore, the possibility of using T. gondii infected cells-derived exosome-alum as a vaccine is a new perspective in toxoplasmosis.

Screening of Plasmodium parasite in vectors and humans in three villages in Aswan Governorate, Egypt.

Egypt has successfully eliminated malaria during 2010-2013, however, between May to mid-June 2014, an outbreak was reported in Al-Adwa village, Aswan Governorate indicating that malaria may be potentially re-emerging in the country. The aim of this work was to reevaluate malaria in Al-Adwa and surrounding villages, 1 year after malaria cases have been reported through entomological and human screening in collaboration with the Ministry of Health and Population. Four trips were conducted during the period from March 2015 to March 2016. Mosquitoes were collected, sorted and identified. Anopheles species were processed for detection of Plasmodium by polymerase chain reaction (PCR), and engorged abdomens in blood-fed mosquitoes were analyzed for host preference using multiplex PCR. Thick and thin blood films were prepared from all apparently healthy children (n = 188) attending El-Sheikh Mostafa preparatory school. Results showed that Anopheles genus existed only in East Al-Adwa village. A total of 38 Anopheles mosquitoes were collected and identified as Anopheles multicolor 70% (A. multicolor), A. sergenti 20% and A. pharoensis 10%. The latter showed 100% human blood preference compared to A. sergenti (20%) and An. multicolor (0%). All female Anopheles were 100% negative for Plasmodium DNA, and all blood films showed no detectable parasite. The absence of Plasmodium in the area under study does not rule out the risk of future infections as the vector is still present together with the imported cases and carriers. Regular screening for the presence of Plasmodium in the area is absolutely paramount for early warning.