Graduate Student Cal Poly, Pomona Pomona, California, United States
Disclosure(s):
Eliana Moisa, BS: No financial relationships to disclose
Introduction/Rationale: Toxoplasma gondii is an apicomplexan parasite that infects a third of the human population through contaminated water or food. Acute infection is characterized by fast replicating tachyzoites that differentiate into dormant bradyzoites. There are no viable vaccines for humans and therapeutic strategies can lead to damaging side effects. Developing an ideal vaccine remains a significant challenge due to the complexities of the T. gondii life cycle. Previous studies have demonstrated exosomes released from tachyzoites lead to partial immunity in mice. Exosomes are extracellular vesicles (EVs) that carry essential cargo that play a role in cellular communication. Although previous studies have shown partial immunity, we aim to investigate if secretion from tachyzoites, bradyzoites, and T. gondii-infected immune cells could lead to long-lasting protection.
Methods: To test this, we isolate these EVs from both type II T. gondii life stages and infected immune cells then confirm their presence through vesicle surface marker CD63 and life stage-specific proteins (SAG-1 and CST-1) using Western blot and microscopy. Additionally, we will immunize C57BL/6 mice by injecting the EVs intramuscularly prior to infection. After infection, survival rates will be monitored in addition to analysis of antibodies and cytokine levels using ELISA.
Results: We have confirmed EV extraction through nanoparticle tracking analysis and found an average vesicle size ranging between 148.0-174.7nm, which aligns with microvesicle size range. After extraction, uninfected immune cells are co-incubated with extracted EVs to measure cytokine levels using ELISA.
Conclusion: Using extracellular vesicles as an immunotherapy is a more recent avenue of research that does not require inserting a live strain of the parasite into humans. There is much to be discovered about using EVs as a method for optimizing immunity which is why it is important to have more focus on the subject within immunology and infectious disease research.
