Particulate based vaccines for cancer immunotherapy

In this thesis we describe our studies aimed at optimizing the efficacy of synthetic long peptide (SLP) vaccines via the encapsulation in Poly-(lactic-co-glycolic acid) (PLGA)particles. Immunotherapy based on SLP-vaccines has resulted in strong tumor specific immune response and importantly, improved clinical benefit in patients with pre-malignant lesions. One important drawback associated with SLP-vaccines is their current form of administration in Montanide, a clinical grade water-in-oil emulsion. The aim of this Ph.D project was to device an alternative method of delivery which overcomes the drawbacks associated with the use of Montanide. For this purpose we explored the use of PLGA (nano)particles (NP) as a delivery vehicle for SLP. Several important aspects for vaccination were assessed in this thesis; from the pharmaceutical formulation to the immunological characterization of different PLGA-SLP preparations. Together, the data presented in this thesis show that PLGA-NP mediated delivery of SLP is a very efficient method to target, load and mature Dendritic cells (DCs) as immune stimulatory compounds can be co-encapsulated with the vaccine AgFinancial support for the publication of this thesis was provided by AZL Onderzoeks- en Ontwikkelingskrediet Apotheek, and ISA Pharmaceuticals, Leiden, The NetherlandsUBL - phd migration 201

Targeting nanoparticles to CD40, DEC-205 or CD11c molecules on dendritic cells for efficient CD8(+) T cell response: A comparative study

Imaging- and therapeutic targets in neoplastic and musculoskeletal inflammatory diseas

Optimization of encapsulation of a synthetic long peptide in PLGA nanoparticles: Low-burst release is crucial for efficient CD8(+) T cell activation

Overlapping synthetic long peptides (SLPs) hold great promise for immunotherapy of cancer. Poly(lactic-co-glycolic acid) (PLGA) nanoparticles (NPs) are being developed as delivery systems to improve the potency of peptide-based therapeutic cancer vaccines. Our aim was to optimize PLGA NP for SLP delivery with respect to encapsulation and release, using OVA24, a 24-residue long synthetic antigenic peptide covering a CTL epitope of ovalbumin (SIINFEKL), as a model antigen. Peptide-loaded PLGA NPs were prepared by a double emulsion/solvent evaporation technique. Using standard conditions (acidic inner aqueous phase), we observed that either encapsulation was very low (1-30%), or burst release extremely high (>70%) upon resuspension of NP in physiological buffers. By adjusting formulation and process parameters, we uncovered that the pH of the first emulsion was critical to efficient encapsulation and controlled release. In particular, an alkaline inner aqueous phase resulted in circa 330nm sized NP with approximately 40% encapsulation efficiency and low (<10%) burst release. These NP showed enhanced MHC class I restricted T cell activation in vitro when compared to high-burst releasing NP and soluble OVA24, proving that efficient entrapment of the antigen is crucial to induce a potent cellular immune response.Clinical Pharmacy and Toxicolog

Environmental Aesthetics. Crossing Divides and Breaking Ground

Clinical Pharmacy and Toxicolog

Efficient ex vivo induction of T cells with potent anti-tumor activity by protein antigen encapsulated in nanoparticles

Experimental cancer immunology and therap

Passive immunization of guinea-pigs with llama single-domain antibody fragments against foot-and-mouth disease

Foot-and-mouth disease (FMD) is a highly contagious disease that occasionally causes outbreaks in Europe. There is a need for therapies that provide rapid protection against FMD in outbreak situations. We aim to provide such rapid protection by passive immunization with llama single-domain antibody fragments (VHHs). Twenty-four VHHs binding serotype O FMDV in vitro were isolated from immunized llamas by phage display and expressed in bakers yeast for further characterization. They recognized four functionally independent antigenic sites. Six strongly FMDV neutralizing VHHs bound to a peptide representing the GH-loop of viral protein 1 known to be involved in binding to the cellular receptor of FMDV. Clone M8, recognizing this antigenic site, and clone M23, recognizing another antigenic site, showed synergistic in vitro virus neutralization. Three FMDV specific VHHs were PEGylated in order to decrease their rapid blood clearance and thus enable in vivo guinea pig protection experiments. Passive immunization with individual VHHs showed no protection, but a mixture of M8 and M23 showed partial transient protection. The protection afforded by these VHHs was however low as compared to the complete protection afforded by convalescent guinea pig serum. In contrast, these VHHs showed far more efficient in vitro FMDV neutralization than convalescent guinea pig serum. This lack of correlation between in vitro neutralization and in vivo protection lends further credence to the notion that opsonophagocytosis of FMDV is important for protection in vivo

Fiber bundle sensor for detection of formaldehyde concentration in fish

We experimentally demonstrate an optical fiber bundle based sensor for measuring formaldehyde concentration in fish. We show that when contaminated fish samples are shined with red laser light with about 630 nm wavelength, the intensity of the backscattered radiation increases linearly with respect to the formaldehyde concentration. Our sensor has a simple architecture, it exhibits good sensitivity, linearity and stability and it has been tested for formaldehyde concentrations ranging from 3% to 21%. Our sensor allows non-destructive, on-site measurements and will have applications towards the development of all-optical cheap and portable sensors for detection of pollutants and toxic chemicals in the food industry and in the agriculture sector, being potentially suitable for measurements in the field

Dendritic cells process synthetic long peptides better than whole protein, improving antigen presentation and T-cell activation

Experimental cancer immunology and therap