Presenter: Dr Julius Oyugi

1. CIHR team grant in HIV vaccine discovery: novel mechanisms and strategies of protectionUniversity of TorontoKAVI University of Nairobi Presenter: Dr Julius Oyugi

2. HIV Vaccine Team University of Toronto • Mario Ostrowski[PI] • Tania Watts • Jen Gommerman • Goetz Erhardt • Rupert Kaul • James Rini • Dana Philpott University of Nairobi • Walter Jaoko[PI] • OmuOnzala. • Julius Oyugi

3. PRINCIPLES • Need for “Back to Basics” approach. • Focus on mucosal sites. • Target HIV immune responses via T cells, B cells and Innate cells.

4. Nature of research collaboration. • Grant uses an iterative approach • Yearly meetings of all members • Cross-fertilization of trainees • Project is primarily discovery and pre-clinical • Industrial partners to be based on promising discoveries.

5. Team grant Themes Theme 1: Optimizing CD8 T cell memory for prophylactic or therapeutic immunization. • An ALVAC strategy[weakly immunogenic and potentially efficacious]. • A VZV strategy [a persistently reactivating immunogen]. Theme #2: Optimizing and targeting mucosal antibody responses.

6. Aim 1: Pre-clinical development of a canarypox (ALVAC) expressing HIV antigens and TNF-SF (tumor necrosis factor superfamily) molecules. • CTL vaccines based on DNA and pox virus vectors do not provide long lived memory T cell responses in humans. • Members of the TNFSF can enhance HIV specific CTL responses by their stimulatory effects on dendritic cells or CD4+ T cells.

7. Plan • Develop ALVAC-SIV-gpe-TNSF vaccine construct • Carry out non-human primate studies

8. Aim 2: Pre-clinical development of immunotherapeutic approaches targeting costimulatory and coinhibitory pathways to improve T cell function in HIV infection. • CTL are exhausted in chronic virus infections. • Build on team members Watts, Ostrowski work: • Tim-3 upregulation and TRAF-1 downregulation are markers of CD8 dysfunction during chronic viral infection • Evaluation of candidate co-stimulatory molecules to improve T cell function including CD40L, 41-BBL, Tim-3 blockade[mice model].

9. Aim 3: Determining the feasability of a persistent replicating virus vector for HIV vaccine development: the role of pre-existing vector immunity on mucosal T cell immunity and activation. • Current DNA/virus vector primer are limited in maintaining long term effector CTL. • Emerging evidence suggests that virus vectors that can continue to induce persistent effector CTL may be preferable[Louis Picker et al, 2011].

10. VZV based Vaccine as a vector Goal is to determine whether a VZV based vaccine could; • Induce mucosal T cell immunity even in the presence of VZV sero-positivity. • To assess the activation state of mucosal sites post VZV vaccination, particularly in those who are VZV sero-positive.

11. Team member McDonald has developed preclinical HIV vaccine candidates based on persistent CMV and VZV vectors. • Plan: • Field work in Kenya evaluating T cell systemic and mucosal immune responses after administration of a licensed VZV vaccine[Team member Walter Jaoko].

12. Aim # 4: Exploring B cells as key cellular players in controlling HIV propagation within mucosal tissues • It is uncertain if B cells are actively recruited to sites of viral replication in the mucosa, and if so, what types of B cells congregate around active foci of viral replication.

13. Team member Gommerman is B cell immunologist • PLAN: • Evaluating B cell subsets in human gut and genital mucosa tissues • Evaluating TNF/iNOS-producing plasma cells at mucosal sites and their role in viral control • Evaluating B cell exhaustion and how to reverse it.

14. Aim 5: To investigate the feasibility of blocking the HIV Env/ T cell integrinα4β7/b1 interaction as a strategy to reduce mucosal acquisition of HIV. • The role of α4β7 in HIV pathogenesis • Homing marker for effector T cells to the gut. • It is capable of binding HIV gp120. • Its expression is associated with increased susceptibility to HIV infection.

15. Team member Dr. Kaul has expertise in mucosal • immunology of gut / genital tract • PLAN: • Assess expression of α4β7 and ligandMAdCAM in genital tissues (cervix, foreskin). • Assess importance of α4β7: HIV target cell susceptibility at mucosal sites. • Work with team member Rini to develop small molecule inhibitors.

16. Aim 6: Nod agonists as vaccine adjuvants Team member Philpott is Nod expert Test ability of candidate NLR agonists to enhance antibody responses at the mucosal level. Progress: Have begun testing Nod 2 agonist (MDP) and a novel nod agonist (AHL) in a DNA vaccine and protein vaccine approach using gp120 in Balb/C mice.

17. Aim 7: Development and standardization of mucosal immune assays focused on B cell responses to be applied to vaccination studies in the Kenyan cohort. • Team member Dr Oyugi and Prof Anzala PLAN: • Assess B cell immunity at the mucosal surface • Development of HIV Ab ELISA using envelopes from early infection, IgG, IgA • B cell ELISpot assay from mucosal surfaces: IgG, IgA Progress: Obtained Envclade A and C during early infection • KAVI personnel training at UT site

18. Obstacles so far • Purchasing equipment and transporting to UN is problematic • Protocol development requires REB approval at both sites • No indirect costs permitted by funder on funds sub-contracted to UN site.

19. ACKNOWLEDGEMENTS • UOT TEAM: [Mario Ostrowski,Tania Watts, • Jen Gommerman,GoetzErhardt, • Rupert Kaul, James Rini, • Dana Philpott]. • UON TEAM [Walter Jaoko, OmuOnzala, • Julius Oyugi]. • CIHR AND GHRI