1. Housekeeping
May 1st 31 field trip, transport yourself to the Shady Lakes, pm.
PCR results gel is posted (report)
This lecture paper discussion
Vaccine; why, possible?
What knowledge required?
Different approaches, failure, success?

3. Take home Why develop parasite vaccines?
What do we need to know to develop a parasite vaccine?
Why parasite vaccine success limited?
Types of vaccines

4. What does a vaccine do ?
Stimulates normal protective immune response of host to fight invading pathogen

8. Vaccines work! Diphtheria Tetanus Measles Mumps Rubella Polio
Hepatitis B  

9. Why parasite vaccines? What is a good vaccine?
Advantages over drugs and disease prevention strategies (“treat and release”)
Part of a control program
History of success in other diseases
What is a good vaccine?
Antigens must evoke specific protective response
Vaccine must stimulate good response
(preferably without adjuvants)
Good level of protection with single treatment

11. Commercial parasite vaccines
Dictyocaulus (nematoda): irradiated larval vaccine.
(Dictol®)
Theileria (apicomplexa): attenuated live vaccines.

12. Parasite vaccines
Ticks: recombinant antigen (TickGARD®)

15. NEED TO KNOW
Life cycle
Understand effective anti-parasite immune mechanism

16. Recombinant Hookworm Adult Secreted Protein

20. Candidates on trial
Consistent, significant protection levels in animal models.
Free from gross tissue side-effects.
Pass recognized toxicity tests - animal
models & human phase I.
Good production record - low costs, stable formulation.

22. VIRUSES Superdomains of life vaccines
Woese, C.R., O. Kandler, & M.L. Wheelis (1990)

23. Obstacles for parasite vaccines
Parasites avoid, interfere with host immune system
Complex life cycles, what are the best targets?
Unknown effective immune mechanisms (Model systems not optimal?)

24. Types of vaccines 1. Whole pathogens, dead
2. Attenuated live or low virulence vaccines.
3. Protein Subunit vaccines.
→ Natural purified proteins.
→ Recombinant protein antigens.
→ Chemical small peptide vaccines.
4. DNA vaccines.

25. Modern techniques help I
Identify protective antigens
Screening cDNA libraries & protein
arrays with infection sera
Cloning gene encoding antigen
Production recombinant form of antigen

26. Modern techniques help II
Natural antigens
animals/parasites
purification, contaminants
Recombinant antigens
cheap production
consistent product (IS IT OK?)

27. DNA vaccine
Gene encoding antigen (DNA) cloned (plasmid), under control of a promotor ↓
Introduce plasmid in patient
Parasite antigen expressed in host cells
Stimulation of immune system