Application of Novel Delivery systems for ASFV antigens


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Presented by Waithaka Mwangi at the African Swine Fever Diagnostics, Surveillance, Epidemiology and Control Workshop, Nairobi, Kenya, 20-21 July 2011

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Application of Novel Delivery systems for ASFV antigens

  1. 1. ASFV Diagnostics, Surveillance, Epidemiology and Control:Identification of Researchable Issues Targeted to the Endemic Areas within sub-Saharan Africa Hosted by BecA-ILRI and sponsored by CSIRO-AusAID Waithaka Mwangi Dept. of Veterinary Pathobiology College of Veterinary Medicine and Biomedical Sciences Texas A&M University
  2. 2. • ASFV is a highly contagious pathogen that causes devastating hemorrhagic fever in pigs with ~100% case mortality rates.• It causes major economic losses, threatens food security, and limits pig production in affected countries.Goal:Develop a vaccine capable of induction of ASFV-specific protectiveimmunity.
  3. 3. p32: immunogenic, implicated in virus internalization, antibody targetp54: Transmembrane, involved in virus particle maturation, antibody targetp72: Main component of the viral capsid, antibody and CTL targetPp220 and pp62 polyproteins:• Produce structural proteins that account for ~32% of the total protein virion mass and are the major components of the core shell• Indispensable for viral replication and production of viable virus
  4. 4. Three synthetic codon-optimized chimeric genes generated: Designated saf1, saf2, and saf3.
  5. 5. • Replication-incompetent adenovirus (Ad5): - Systemic and mucosal immunization • Bacillus subtilis: mucosal immunization
  6. 6. Evaluate immunogenicity and protective efficacy of the lead vaccine candidates following intradermal or mucosalimmunization with recombinant adenovirus (rAd) or Bacillus (rBa), respectively, expressing saf1, saf2, and saf3.
  7. 7. Immunization of pigs with adenovirus- or Bacillus-vectored ASFVchimeric antigens will confer systemic and/or mucosal immunity against ASFV Specific Aims:• Test whether intradermal or mucosal immunization of pigs with rAdSAF1-3 will confer protection against ASFV challenge.• Test whether mucosal immunization of pigs with rBaSAF1-3 will confer protection against mucosal ASFV challenge.
  8. 8. Positive clone 1 2 3 4 5 6 7 8 9 10 11 Test cloneNegative control Mwangi, W., et al., 2011
  9. 9. Generation of rAdenovirusA) B) C)Immunocytometric analysis of 293A cells infected with; A and B) rAdFMD virus; and C) control adenovirus. A and C) were probed with anti-FLAG AP-conjugated mAb, B was probed with an isotype-matched AP-conjugated mAb. Mwangi, W., et al 2011
  10. 10. A) B)Immunization of calves with a single dose of the rAdFMD vaccine primed significant;A) FMD1-specific IFN-γ-secreting T cell responses; and B) FMD1-specific T cell proliferation, detectable in seven days. Mwangi, W., et al 2011
  11. 11. 450 400 603 605 350# spot/10E5 cells 300 250 200 150 100 50 0 PHA O1Campos FMDV1 10 ug FMDV1 30 ug PBS Filgueira, M.P., et al., 2011
  12. 12. IgA values: calculated as the S/P ratio = (sample – negative control)/(positive – negative control). Hargis, B.M., et al 2011
  13. 13. Hydropathic profile of the SAF1 chimeric polypeptide
  14. 14. A) B) C) D) Immunocytometric analysis of 293A cells transfected with: A) SAFI; B) SAFII; C) SAFIII expression constructs; and D) vector control The cells were probed with anti-FLAG AP-conjugated mAb. Mwangi, W., et al 2011
  15. 15. • Recombinant SAFI-III proteins• Recombinant Adenovirus-SAFI-III• Recombinant B. subtilis-SAFI-IIIQuality control analysis
  16. 16. Conduct dose-escalation immunization studies in pigs • Evaluate SAFI-III-specific immune responses • Evaluate recall responses upon boost - test sera for recognition of native ASFV antigens - test T cells for reactivity against ASF virus • identify dose required to induce optimal immune responses
  17. 17. Conduct immunization studies in pigs; • Prime Evaluate SAFI-III-specific immune responses • Boost • Challenge • Protective index: Survival
  18. 18. DC-targeted Control Mwangi, W., et al., 2011
  19. 19. A 1 wk post-immunization 3 wks post-immunization 250 ∗ ∗p<0.001 500 ∗ ∗p<0.001IFN- γ + SFC/106 CD8-γ δ -PBMC IFN- γ + SFC/106 CD8-γ δ -PBMC 200 400 150 300 100 200 50 100 0 0 pCC98MSP1 pICMSP1 Vector pCC98MSP1 pICMSP1 Vector Mwangi, W., et al., 2011
  20. 20. A 19 wks post-immunization 1 wk post-Boost ∗ ∗p<0.001 ∗ ∗p<0.001 Mwangi, W., et al., 2011
  21. 21. Mwangi Lab: Jocelyn Bray, Shehnaz Lokhandwala, Ann-MarrieSurya Waghela Texas A&M University Luc Berghman, Texas A&M UniversityMariano Pérez- Filgueira, Instituto de Virología, CICVyA, INTA- Castelar, ArgentinaBilly M. Hargis University of ArkansasRichard Bishop ILRI in collaboration with DVS, Kenya and CINA-INIA, Valdeolmos, Spain