Attenuated plasmodium sporozoite expressing MAGE-A3 induces antigen-specific CD8+ T cell response against lung cancer in mice

Objective: Cancer vaccines that rely on tumor antigen-specific CD8^+ T cell responses, are promising anti-cancer adjuvant immunotherapies. This study investigated whether genetically attenuated Plasmodium sporozoite(GAS) could be used as a novel vector to induce antigen-specific CD8^+ T cell responses against lung cancer.Methods: We constructed GAS/MAGE-A3, a recombinant GAS engineered to express the lung cancer-specific antigen, melanomaassociated antigen 3(MAGE-A3), and assessed its therapeutic effects against lung cancer.Results: Robust parasite-specific CD8αlow CD11ahigh and CD49dhigh CD11ahigh CD4^+ T cell responses as well as a MAGE-A3-specific CD8^+ T cell response were induced in GAS/MAGE-A3-immunized mice. Adoptive transfer of GAS/MAGE-A3-induced CD8^+ T cells from HLA-A2 transgenic mice into lung cancer-bearing nude mice inhibited tumor growth and prolonged survival.Conclusions: These findings demonstrate that GAS/MAGE-A3 induces a strong MAGE-A3-specific CD8^+ T cell response against lung cancer in vivo, and indicate that GAS is a novel and efficacious antigen delivery vector for antitumor immunotherapy.

Preparation of Sporozoite Antigen of E. tenella

[Objective] To provide antigen for preparation of monoclonal antibodies against E. tenella. [Method] Broiler chickens were inoculated with axenic culture of sporulated oocysts of E. tenella, and their feces were collected after 5 -10 d. After simple separation, the oocysts were spor- ulated, purified and counted to prepare sporozoite antigen. [ Result] This method used to prepare sporozoite antigen was simpler and easier than other methods. In addition, it required few specialized equipment and media, and it could be conducted in general laboratories. However, it needed long time. [ Condusion] The E. tenella oocysts have been isolated from chickens, and the sporozoite antigen with high protein concentration has been obtained.

A Protocol for a Highly Consistent, High Level Production <i>in Vivo</i>of <i>Plasmodium falciparum</i>Oocysts and Sporozoites

Investigation of the intimate relationship between the human malaria parasite Plasmodium falciparum and its Anopheles vector requires the reliable production and isolation of successive sexual stages of the parasite from infected mosquitoes. Such an advance in propagation would benefit a range of molecular, cellular, immunochemical and transmission-blocking research studies. Parasite cultivation, mosquito rearing, infection and subsequent dissection of mosquitoes are all highly technical procedures that require both skill and experience to perform with competence. Furthermore, to produce mosquitoes of an appropriate age to infect during the short period in which parasites are viable for infection demands precise planning in order to coordinate the interacting life cycles of the parasite and vector. Here, a protocol is described for the complete development of P. falciparum within Anopheles stephensi. A very consistent, high level production in vivo of P. falciparum oocysts and sporozoites is demonstrable by dissection of the mosquito midgut and salivary glands, respectively.

Effect of hepatocyte growth factor signaling pathway activation on Plasmodium berghei infection

Objective:To explore the effect of hepatocyte growth factor signaling pathway activation on Plasmodium berghei infection.Methods:In this study,hepatocyte growth factor was detected by ELISA and Western blotting assay.Hepatocyte injury was detected by FITC-dextran absorption assay,and hepatocyte growth factor expression was shown to be expressed in the same injury cells by immunofluorescence against hepatocyte growth factor.In addition,Activation of hepatocyte growth factor and its receptor signaling pathway was detected with immunoprecipitation and detection of phosphorylation status.Results:It was found that injury of hepatocytes by sporozoite migration induced the secretion of hepatocyte growth factor and it was hepatocyte growth factor that rendered hepatocytes susceptible to Plasmodium sporozoite infection.In addition,hepatocyte infections depended on activation of the hepatocyte growth factor and its receptor signaling pathway.Conclusions:Our results indicate that hepatocyte growth factor and its receptor may possibly be potential targets for new approaches to malaria treatment.