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Over the past decade, the development of macromolecular drugs based on peptides, proteins and nucleic acids has increased the interest in microparticulate drug delivery, i.e., the delivery of drug systems in the nanometer and micrometer ranges. However, little is known so far about the effect that microparticulate systems have on various tissues after administration. Additionally, the knowledge of mechanisms responsible for the uptake and transport of microparticles across the human intestine is incomplete and requires further investigation to improve both the safety profiles and the efficiency of these drug delivery systems. This thesis is comprised of two parts. The first one investigates gene expression responses obtained from DNA arrays in local and distal tissues after microparticulate drug delivery. The second part focuses on the mechanisms responsible for the transport of microparticles across epithelial cells lining the intestine. The results presented in the first part demonstrated that gene expression analysis offers a detailed picture of the tissue responses after intramuscular or pulmonary administration of microparticulate drug delivery systems compared to the traditional techniques used for such evaluations. In addition, DNA arrays provided a useful and sensitive tool for the initial characterization and evaluation of both local and distal tissue responses, making it possible to distinguish between gene expression patterns related to each studied delivery system. The results presented in the second part demonstrated that the surface properties of the microparticle were important for the extent of transport across an in vitro model of the follicle-associated epithelium (FAE), comprised of intestinal epithelial cells specialized in particle transport (M cells). Another important finding was that the enteropathogen bacterium, Yersinia pseudotuberculosis, induced microparticle transport across the normal intestinal epithelium, represented by Caco-2 cells a

Over the past decade, the development of macromolecular drugs based on peptides, proteins and nucleic acids has increased the interest in microparticulate drug delivery, i.e., the delivery of drug systems in the nanometer and micrometer ranges. However, little is known so far about the effect that microparticulate systems have on various tissues after administration. Additionally, the knowledge of mechanisms responsible for the uptake and transport of microparticles across the human intestine is incomplete and requires further investigation to improve both the safety profiles and the efficiency of these drug delivery systems. This thesis is comprised of two parts. The first one investigates gene expression responses obtained from DNA arrays in local and distal tissues after microparticulate drug delivery. The second part focuses on the mechanisms responsible for the transport of microparticles across epithelial cells lining the intestine. The results presented in the first part demonstrated that gene expression analysis offers a detailed picture of the tissue responses after intramuscular or pulmonary administration of microparticulate drug delivery systems compared to the traditional techniques used for such evaluations. In addition, DNA arrays provided a useful and sensitive tool for the initial characterization and evaluation of both local and distal tissue responses, making it possible to distinguish between gene expression patterns related to each studied delivery system. The results presented in the second part demonstrated that the surface properties of the microparticle were important for the extent of transport across an in vitro model of the follicle-associated epithelium (FAE), comprised of intestinal epithelial cells specialized in particle transport (M cells). Another important finding was that the enteropathogen bacterium, Yersinia pseudotuberculosis, induced microparticle transport across the normal intestinal epithelium, represented by Caco-2 cells a

Over the past decade, the development of macromolecular drugs based on peptides, proteins and nucleic acids has increased the interest in microparticulate drug delivery, i.e., the delivery of drug systems in the nanometer and micrometer ranges. However, little is known so far about the effect that microparticulate systems have on various tissues after administration. Additionally, the knowledge of mechanisms responsible for the uptake and transport of microparticles across the human intestine is incomplete and requires further investigation to improve both the safety profiles and the efficiency of these drug delivery systems. This thesis is comprised of two parts. The first one investigates gene expression responses obtained from DNA arrays in local and distal tissues after microparticulate drug delivery. The second part focuses on the mechanisms responsible for the transport of microparticles across epithelial cells lining the intestine. The results presented in the first part demonstrated that gene expression analysis offers a detailed picture of the tissue responses after intramuscular or pulmonary administration of microparticulate drug delivery systems compared to the traditional techniques used for such evaluations. In addition, DNA arrays provided a useful and sensitive tool for the initial characterization and evaluation of both local and distal tissue responses, making it possible to distinguish between gene expression patterns related to each studied delivery system. The results presented in the second part demonstrated that the surface properties of the microparticle were important for the extent of transport across an in vitro model of the follicle-associated epithelium (FAE), comprised of intestinal epithelial cells specialized in particle transport (M cells). Another important finding was that the enteropathogen bacterium, Yersinia pseudotuberculosis, induced microparticle transport across the normal intestinal epithelium, represented by Caco-2 cells a

Over the past decade, the development of macromolecular drugs based on peptides, proteins and nucleic acids has increased the interest in microparticulate drug delivery, i.e., the delivery of drug systems in the nanometer and micrometer ranges. However, little is known so far about the effect that microparticulate systems have on various tissues after administration. Additionally, the knowledge of mechanisms responsible for the uptake and transport of microparticles across the human intestine is incomplete and requires further investigation to improve both the safety profiles and the efficiency of these drug delivery systems. This thesis is comprised of two parts. The first one investigates gene expression responses obtained from DNA arrays in local and distal tissues after microparticulate drug delivery. The second part focuses on the mechanisms responsible for the transport of microparticles across epithelial cells lining the intestine. The results presented in the first part demonstrated that gene expression analysis offers a detailed picture of the tissue responses after intramuscular or pulmonary administration of microparticulate drug delivery systems compared to the traditional techniques used for such evaluations. In addition, DNA arrays provided a useful and sensitive tool for the initial characterization and evaluation of both local and distal tissue responses, making it possible to distinguish between gene expression patterns related to each studied delivery system. The results presented in the second part demonstrated that the surface properties of the microparticle were important for the extent of transport across an in vitro model of the follicle-associated epithelium (FAE), comprised of intestinal epithelial cells specialized in particle transport (M cells). Another important finding was that the enteropathogen bacterium, Yersinia pseudotuberculosis, induced microparticle transport across the normal intestinal epithelium, represented by Caco-2 cells a

Polyacryl starch microparticles have been developed as an oral vaccine adjuvant capable of inducing strong local and systemic immune responses in mice. In this thesis, the starch microparticles were studied in order to increase basic understanding of their function. In particular, the thesis addressed aspects of the uptake of the particles and their presentation to the immune system after different routes of administration, in correlation with the differentiation of the induced immune response. When using human serum albumin as a model antigen conjugated to the microparticles, it was found that the route of administration and the use of different combinations of routes, parenteral or oral, affect the profile (Th1/Th2 balance) of the induced immune response. It was also found that oral boosters are needed for the development of a local s-IgA response. Ligated mouse intestinal loops in combination with confocal laser-scanning microscopy demonstrated that the uptake of the particles by the intestinal mucosa takes place over the follicle-associated epithelium (FAE) that covers the Peyer’s patches. The particles are also taken up in the villus epithelium when conjugated with rCTB, a ligand to the GM1 receptor. This qualitative difference in uptake did not affect the induced immune response. Thus, the addition of rCTB to the microparticles did not improve or influence the profile of the immune response. Chronic stress, known to alter the barrier function of the FAE, increased the cellular response but did not affect the humoral immune response. Despite positive results in rodents, the particles were not able to boost a humoral immune response in man when tested with diphtheria toxin-cross reacting material (CRM197). Possible methods of improving the adjuvant effect in man are discussed.

Polyacryl starch microparticles have been developed as an oral vaccine adjuvant capable of inducing strong local and systemic immune responses in mice. In this thesis, the starch microparticles were studied in order to increase basic understanding of their function. In particular, the thesis addressed aspects of the uptake of the particles and their presentation to the immune system after different routes of administration, in correlation with the differentiation of the induced immune response. When using human serum albumin as a model antigen conjugated to the microparticles, it was found that the route of administration and the use of different combinations of routes, parenteral or oral, affect the profile (Th1/Th2 balance) of the induced immune response. It was also found that oral boosters are needed for the development of a local s-IgA response. Ligated mouse intestinal loops in combination with confocal laser-scanning microscopy demonstrated that the uptake of the particles by the intestinal mucosa takes place over the follicle-associated epithelium (FAE) that covers the Peyer’s patches. The particles are also taken up in the villus epithelium when conjugated with rCTB, a ligand to the GM1 receptor. This qualitative difference in uptake did not affect the induced immune response. Thus, the addition of rCTB to the microparticles did not improve or influence the profile of the immune response. Chronic stress, known to alter the barrier function of the FAE, increased the cellular response but did not affect the humoral immune response. Despite positive results in rodents, the particles were not able to boost a humoral immune response in man when tested with diphtheria toxin-cross reacting material (CRM197). Possible methods of improving the adjuvant effect in man are discussed.

Polyacryl starch microparticles have been developed as an oral vaccine adjuvant capable of inducing strong local and systemic immune responses in mice. In this thesis, the starch microparticles were studied in order to increase basic understanding of their function. In particular, the thesis addressed aspects of the uptake of the particles and their presentation to the immune system after different routes of administration, in correlation with the differentiation of the induced immune response. When using human serum albumin as a model antigen conjugated to the microparticles, it was found that the route of administration and the use of different combinations of routes, parenteral or oral, affect the profile (Th1/Th2 balance) of the induced immune response. It was also found that oral boosters are needed for the development of a local s-IgA response. Ligated mouse intestinal loops in combination with confocal laser-scanning microscopy demonstrated that the uptake of the particles by the intestinal mucosa takes place over the follicle-associated epithelium (FAE) that covers the Peyer’s patches. The particles are also taken up in the villus epithelium when conjugated with rCTB, a ligand to the GM1 receptor. This qualitative difference in uptake did not affect the induced immune response. Thus, the addition of rCTB to the microparticles did not improve or influence the profile of the immune response. Chronic stress, known to alter the barrier function of the FAE, increased the cellular response but did not affect the humoral immune response. Despite positive results in rodents, the particles were not able to boost a humoral immune response in man when tested with diphtheria toxin-cross reacting material (CRM197). Possible methods of improving the adjuvant effect in man are discussed.

Polyacryl starch microparticles have been developed as an oral vaccine adjuvant capable of inducing strong local and systemic immune responses in mice. In this thesis, the starch microparticles were studied in order to increase basic understanding of their function. In particular, the thesis addressed aspects of the uptake of the particles and their presentation to the immune system after different routes of administration, in correlation with the differentiation of the induced immune response. When using human serum albumin as a model antigen conjugated to the microparticles, it was found that the route of administration and the use of different combinations of routes, parenteral or oral, affect the profile (Th1/Th2 balance) of the induced immune response. It was also found that oral boosters are needed for the development of a local s-IgA response. Ligated mouse intestinal loops in combination with confocal laser-scanning microscopy demonstrated that the uptake of the particles by the intestinal mucosa takes place over the follicle-associated epithelium (FAE) that covers the Peyer’s patches. The particles are also taken up in the villus epithelium when conjugated with rCTB, a ligand to the GM1 receptor. This qualitative difference in uptake did not affect the induced immune response. Thus, the addition of rCTB to the microparticles did not improve or influence the profile of the immune response. Chronic stress, known to alter the barrier function of the FAE, increased the cellular response but did not affect the humoral immune response. Despite positive results in rodents, the particles were not able to boost a humoral immune response in man when tested with diphtheria toxin-cross reacting material (CRM197). Possible methods of improving the adjuvant effect in man are discussed.