1. Live Attenuated Malaria Vaccine
Tzu-Hao Yen
Jeremy Katusak
Blas Quiroga

2. What is a Live Attenuated Vaccine?
A weakened living pathogen that retains all of its antigenic properties, but can no longer cause a pathological condition.

3. Why Live Attenuated Vaccines?
Advantages:
Mimic natural infection  builds up immunity
In comparison to highly purified subunit vaccines, they are relatively cheap to produce and less sophisticated downstream processes are required
Most effective type of vaccine

4. Purified/Concentrated/Inactivated
Vaccine Production
Viral Strain
Master Seed
Working Seed
Inoculation
Single Harvest
Viral strain  kill the virus
Master seed  most pure, free from impurities
Working seed  produced from master seed
Inoculation  put them in media to grow
Single harvest and purified  inactivate. (temperature, chromatography, microfluidizer)
Final  Dilute
Purified/Concentrated/Inactivated
Final Bulk + Filling
Final Product

5. Known Virus Vaccines Measles Vaccine Mumps Vaccine Rubella Vaccine
Oral Polio Vaccine
Chicken Pox Vaccine
Smallpox Vaccine

6. Article Background Plasmodium falciparum sporozoites immunogen (PfSPZ)
New vaccine
Protected through hepatic CD8+ cell immunity
4/25/2017
DRAFT

7. Article Overview Live attenuated malaria vaccine
Based on Pf sporozoites
Protected by hepatic CD8+ cells in the liver

8. Human Study 80 healthy participants ages 18–50 Split into four groups
Exposed to several hundred mosquitoes in a surface area of 56 cm2
It is near impossible to replicate mosquito bite
Note: SC stands for subcutaneously and ID stands for intradermally

9. Human Study
Analysis: Blood smears and sera analysis/assays performed two weeks after each dose to rule out breakthrough infection
Follow up: Three weeks after final dose, volunteers from groups 1, 2, and 4, as well as 18 nonimmunized control volunteers were exposed to mosquitoes infected with PfSPZ
Again, analysis was performed

10. Primate Study
Rhesus macaques immunized in the same manner as humans (SC vs IV)
Exposure was performed through IV inoculation
This was done to observe likely immune responses
Assays were performed at 2 weeks and 3 to 4 months after immunizations

11. Rabbit Study
New Zealand white rabbits immunized four times at 2-week intervals
PfSPZ administered in two injections at subscapular (below shoulder blade)region and via IV injection
Sera analysis performed 2 weeks after the fourth dose

12. Mouse Study
Performed to see if IV administration of irradiated PySPZ could induce high-level protective immunity
Is this higher than previously evaluated ID and SC administration???
Exposure performed through IV inoculation and mosquito exposure
Blood smears were made 7 and 14 days after second exposure (after immunization)

13. Results
Volunteers were immunized by bite of irradiated, PfSPZ infected mosquitos
Exposed to several hundred mosquitos
Each with <0.5 microliters in infected saliva
Surface area~56cm^2
Conducted over 4 weeks
Ages 18-50

14. Results Some volunteers developed modest antibody responses to SPZ
T cell responses were low so doses of asceptic PfSPZ were increased
100% in group 4, 9/9 developed T cell responses
Vaccine was well tolerated and safe
Determine if protection could be improved by altering route of immunization

15. Results
NHP and rabbit studies were conducted for studying further immune responses
Results were graphed 2 weeks and 3-4 months after vaccination
None of the animals had positive T cell responses
Revealed there was limited durability in immunity

16. Results
A-PBMC’s were analyzed for PfSPZ-specific cytokine producing T cells
B-SPICE analysis was used to divide the T cell responses into 7 populations
C-cytokine T-cells individually
D-distribution of PfSPZ-specifics at peak response

17. Results
A-total frequency of PfSPZ cytokine producing CD8+ andCD4+ T Cells in the liver
B-same as last but for T cells isolated from NHPs
C-combination of cytokine producers, CD8+ and CD4+ T cells for individual NHPs
D-same as last slide

18. Future improvement Additional testing is necessary
Available for treating patients
Non-intravenous application of the vaccine
Additional research is also necessary

19. References
Epstein, J. E., K. Tewari, and K. E. Lyke. "Live Attenuated Malaria Vaccine Designed to Protect Through Hepatic CD8+ T Cell Immunity." Sciencemag.org. HighWire Press, 28 Oct Web. 25 Nov <
Epstein, J. E., K. Tewari, and K. E. Lyke. "Supporting Online Material for:Live Attenuated Malaria Vaccine Designed to Protect Through Hepatic CD8+ T Cell Immunity." Sciencemag.org. HighWire Press, 28 Oct Web. 25 Nov <
4/25/2017
DRAFT