Inducing Antibodies with Rationally-designed HIV Vaccines

1. Inducing Antibodies with Rationally-designed HIV Vaccines Susan Zolla-Pazner, Ph. D. New York University School of Medicine Department of Pathology

2. Problems with Whole Env Immunogens • Sequence and antigenic diversity • Conformational masking of critical epitopes • Evolution to escape the effects of Abs • Poor induction of Abs with broad anti-viral functions • Inability as a vaccine reagent to induce a long-lived Ab response (<6 months)

3. Antigenic Determinants on the HIV Envelope V3 loop gp120 gp41 Modified from D R Burton, R A Weiss Science 2010;329:770-773 Published by AAAS

4. Structural Vaccinology Approach • Required steps: • Generate neutralizing monoclonal Abs • Select mAbs with broad reactivity • Crystallize mAbs • Analyze bioinformatics data • Model the epitope • Design and generate recombinant epitope-scaffold immunogens • Immunize animals • Assess immune response Study Ab Study Epitope In vivo Studies

5. Structural Vaccinology Approach • Required steps: • Generate neutralizing monoclonal Abs • Select mAbs with broad reactivity • Crystallize mAbs • Analyze bioinformatics data • Model the epitope • Design and generate recombinant epitope-scaffold immunogens • Immunize animals • Assess immune response Study Ab Study Epitope In vivo Studies

6. Structural Vaccinology Approach • Required steps: • Generate neutralizing monoclonal Abs • Select mAbs with broad reactivity • Crystallize mAbs • Analyze bioinformatics data • Model the epitope • Design and generate recombinant epitope-scaffold immunogens • Immunize animals • Assess immune response Study Ab Study Epitope In vivo Studies

7. Crystallographic Analysis of Anti-V3 mAbs Complexed with V3 Peptides V3/mAb 447: “Ladle-like” V3 binding V3/mAb 2219: “Cradle-like” V3 binding (V. Burke et al, Structure, 2009)

8. Structural Vaccinology Approach • Required steps: • Generate neutralizing monoclonal Abs • Select mAbs with broad reactivity • Crystallize mAbs • Analyze bioinformatics data • Model the epitope • Design and generate recombinant epitope-scaffold immunogens • Immunize animals • Assess immune response Study Epitope

9. Two-thirds of the 35 Residues in V3 are Conserved

10. Structural Vaccinology Approach • Required steps: • Generate neutralizing monoclonal Abs • Select mAbs with broad reactivity • Crystallize mAbs • Analyze bioinformatics data • Model the epitope • Design and generate recombinant epitope-scaffold immunogens • Immunize animals • Assess immune response Study Epitope

11. The Conserved Structure of the V3 Crown A Hydrophilic face of circlet Arch Band Hydrophobic face of circlet Almond et al., ARHR 2010. Jiang et al., Nature Struct. Mol. Biol., 2010

12. Structural Vaccinology Approach • Required steps: • Generate neutralizing monoclonal Abs • Select mAbs with broad reactivity • Crystallize mAbs • Analyze bioinformatics data • Model the epitope • Design and generate recombinantepitope-scaffold immunogens • Immunize animals • Assess immune response Study Epitope

13. Design of Recombinant V3-scaffold Immunogen Example: V3-Cholera Toxin B M. Totrov et al., Virology, 2010.

14. Structural Vaccinology Approach • Required steps: • Generate neutralizing monoclonal Abs • Select mAbs with broad reactivity • Crystallize mAbs • Analyze bioinformatics data • Model the epitope • Design and generate recombinant epitope-scaffold immunogens • Immunize animals • Assess immune response

15. Immunization Protocol B2 P1 P2 P3 B1 gp120 DNA prime V3-CTB boost 6 weeks 6 weeks 4 weeks 2 weeks Post-boost Pre-bleed

16. 50% Neutralizing Ab Response vs. Tier 1 Viruses O O O O 2/5 Responders: 1/5 3/5 4/5 5/5 O 1:100-999 1:10-99 1:1000-9999 >1:10,000

17. 50% Neutralizing Ab Responses vs. Standard Tier 2 Panel of Clade B and C Viruses O O O O Responders: O 1/5 2/5 3/5 4/5 5/5 NT50 = 1:10-99

18. D % Neutralization vs. Bx08 Weeks Neutralizing Abs are Detectable 60 Weeks after the Last Boost

19. Antigenic Determinants on the HIV Envelope V2 loop gp120 gp41 Modified from D R Burton, R A Weiss Science 2010;329:770-773 Published by AAAS

20. Functions of the V2 Loop • Not essential for infectivity • Binds to α4β7 integrin on activated T cells • With V3, protects the chemokine receptor binding site

21. Planned Design of V2 Immunogens • Use the same structural vaccinology approach as used for V3. • Identify “hidden” conserved structure within the 2nd variable loop. • Engraft this generic structure into a scaffold. • Use V2-scaffold as a boost to elicit cross-reactive V2 Abs with multiple anti-viral functions.

22. V2 V3 V2 and V3 are Similar in Their Patterns of Amino Acid Conservation V2 V3 (S. Zolla-Pazner and T. Cardozo, 2010)

23. Conclusions: #1 • The structural vaccinology approach has succeeded in inducing cross-clade neutralizing Abs based on the use of a gp120 DNA prime and a V3-scaffold protein boost. • The development of the boost was the result of revealing a generic conservedstructure with the third sequence “variable region”. • This prime/boost vaccine approach can focus the Ab response on selected epitopes. • Neutralizing Abs were detectable >1 year after the last boost.

24. Conclusions: #2 • More than one epitope needs to be targeted for an effective vaccine. • The same principles that guided the successful development of the V3-scaffold immunogens are being applied to V2, and can ultimately be applied to more complex epitopes (QNE, CD4bs, etc.)

25. NYU School of Medicine Mirek Gorny Sandy Sharpe Cohen Connie Williams Barbara Volsky Xiang-Peng Kong Xunqing Jiang Tim O’NealTim Cardozo David Almondy James Swetnam Suman Laal Phillipe Nyambi Valicia Burke Xunqing Jiang Higuang Li Jared Sampson Brett Spurrier April Killikelly Collaborators University of Massachusetts School of Medicine Shan Lu Shixia Wang Molsoft, Inc. Max Totrov Ruben Abagyan Harvard Medical School Michael Seaman NYU Medical Center