Degree Type

Dissertation

Date of Award

2015

Degree Name

Doctor of Philosophy

Department

Chemical and Biological Engineering

First Advisor

Balaji Narasimhan

Abstract

Vaccine development has had a profound impact on healthcare across the world. However, there are still multiple challenges that current strategies need to overcome to be able to deliver highly targeted and easily administered efficacious vaccines. Specifically, viral infections with high mutation rates have become a difficult target for such therapies. Among these, Human Immunodeficiency Virus (HIV) is one of the major concerns for researchers due to ability of the virus to mutate and the rate of new infections in remote locations. Since traditional approaches have not had great success against these infections, development of novel platforms using single-dose actively targeted vaccinations is a promising alternative. This work focused on the design and evaluation of a targeted polymeric nanovaccine against this virus, with polyanhydride nanoparticles playing dual roles as delivery vehicle and adjuvant. The work presented in this dissertation describes the development of a rationally designed targeted polyanhydride nanovaccine against HIV.

Initial research was focused on the screening of different polyanhydride nanoparticle formulations and understanding cell-particle interactions using antigen presenting cells (APCs), which are key components in the initiation of an immune response. These experiments were aimed at understanding the role that chemistry and surface functionalization had in the preservation of the structure and biological activity of an HIV antigen, and particle internalization and release kinetics, to rationally select lead candidates, and to evaluate their ability to stimulate dendritic cells. The results showed that all nanovaccine formulations used were able to stabilize and sustain antigen release; however, amphiphilic chemistries were specifically identified as lead candidates due to their smaller initial burst release and ability to preserve antigenicity of fragile proteins. In addition, carbohydrate functionalization was not detrimental to the ability of these nanovaccines to release antigen and stimulate dendritic cells. In order to further understand the interactions of polyanhydride nanoparticles with APCs after administration to the body, experiments were carried to analyze the role of complement receptor 3, serum proteins and polymer chemistry in the uptake of these nanoformulations. The results of this investigation showed the complex relationship between the aforementioned factors, which affected the ability of the polyanhydride nanoparticles to be taken up by and stimulate macrophages. The overall observations from these studies were then used to identify the desired characteristics of these polymeric formulations to proceed with in vivo evaluation of these nanovaccines.

The latter chapters of this dissertation were focused on the evaluation of the ability of the lead nanovaccine formulations to elicit immune responses using in vivo models. Before performing efficacy studies with carbohydrate-functionalized polyanhydride nanoparticles, it was necessary to assess the safety of these novel biomaterials; therefore, safety and biodistribution experiments were performed with carbohydrate-functionalized polyanhydride nanoparticles. Histopathology evaluation of tissue samples, quantification of urine and serum biomarkers, cellular distribution and cytokine secretion confirmed that the functionalization of the nanoparticles did not dramatically affected the behavior of the nanoformulations and did not cause any detrimental effects when compared to saline treatments. Finally, evaluation of immune responses generated after the administration of polyanhydride nanovaccines using an HIV antigen in in vivo models was carried out. These formulations were able to induce germinal center B cell formation in draining lymph nodes and generate serum antibodies, eliciting more robust responses than traditional adjuvants (such as Alum). The results of this investigation confirm the ability of polyanhydride nanovaccines to generate potent immune responses and to induce both humoral and cellular immunity. In summary, the studies described herein demonstrate the promising capabilities of polyanhydride nanovaccine formulations to design an efficacious vaccine against viral pathogens.

Copyright Owner

Julia Eulalia Vela Ramirez

Language

en

File Format

application/pdf

File Size

259 pages

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