Characterization of dendritic cells used in an anti-HIV therapeutic vaccine phase I/II clinical trial

Author(s)

Laís Teodoro da Silva

• Document type: Doctoral Thesis
• Press: São Paulo.
• Institution: Universidade de São Paulo (USP). Faculdade de Medicina (FM/SBD)
• Defense date: 2017-03-08

Examining board members

Telma Miyuki Oshiro Sumida; Gil Benard; Daniela Santoro Rosa; Maria Notomi Sato

• Advisor: Telma Miyuki Oshiro Sumida

Abstract

INTRODUCTION: Immunotherapy based on monocyte-derived dendritic cells (MDDCs) is a promising strategy for the treatment of HIV-infected individuals. Due their plasticity, using different combinations of cytokines cocktail in vitro it is possible to obtain a heterogeneous MDDCs population. Consequently the capacity of these cells to secrete cytokines and express molecules that participate in antigen presentation varies (MHC, adhesion and costimulatory molecules) and can interfere in the profile and efficacy of the immune response induced by this therapy. A clinical trial was conducted in our laboratory to evaluate a immunotherapy based on dendritic cells sensitized with autologous inactivated HIV for the treatment of antiretroviral naive chronically HIV-infected individuals. Therefore, it was a good opportunity to study deeply the virus production and expansion in vitro and to characterize MDDCs used as a vaccine. OBJECTIVE. To characterize MDDCs in context of their phenotype and function as well as investigating viral production and expansion in autologous and allogenic systems. METHODS: 17 patients underwent apheresis before vaccination and their peripheral blood mononuclear cells (PBMCs) were used for autologous virus production and expansion of the virus was carried out in both autologous and allogenic systems. Monocytes were differentiated into immature MDDCs that were pulsed/or not with autologous chemically (aldrithiol-2) inactivated HIV particles (HIV-AT-2). These pulsed (HIV-AT-2 MDDCs) and non-pulsed (mature MDDCs) cells were then activated by proinflammatory cytokines. Phenotypic (cell surface marker) and functional analysis (phagocytosis, transmigration and cytokines production) of MDDCs and their priming and stimulation of lymphocyte (proliferation, polyfunctionality and cytotoxicity) was performed using flow cytometry. RESULTS. Viral yield was higher when expanded in allogenic compared to autologous system. After stimulation with proinflammatory cytokines, both HIV-AT-2 MDDCs and mature MDDCs presented increased costimulation expression, activation and migratory molecules compared to immature MDDCs. Regarding to functional characterization, we observed that MDDCs were able to phagocytize FITC-Dextran and exhibitted a low migratory potential and low production of Th1 polarizing response cytokines. Moreover we observed reduced cytotoxic activity induced by HIV-AT-2 MDDCs and mature MDDCs. On the other hand we also observed that HIV-AT-2 MDDCs were capable of inducing proliferation and polyfunctionality of autologous CD4+ and CD8+ T-lymphocytes compared to mature MDDCs. CONCLUSION. Allogenic system was found to be more efficient in increased viral yield in relation to autologous system. Besides, virus expanded in allogenic system showed a more immunogenic profile. Vaccine product (HIV-AT-2 MDDCs) was able to induce antigen specific polyfunctional response (AU)

• FAPESP's process: 12/17822-0 - Characterization of dendritic cells used in a Phase I/II clinical trial of an anti-HIV therapeutic vaccine
• Grantee: Laís Teodoro da Silva
• Support Opportunities: Scholarships in Brazil - Doctorate (Direct)