This thesis focuses on using liposomes in two different treatment strategies; vaccination (or immunotherapy) and delivery of a small molecule, and in two different disease models; cancer and... Show moreThis thesis focuses on using liposomes in two different treatment strategies; vaccination (or immunotherapy) and delivery of a small molecule, and in two different disease models; cancer and atherosclerosis. For each of these treatment strategies, the liposomal formulation was tailored to obtain the desired therapeutic effect. Chapter 2 reviews some of the most important physicochemical properties (size, shape, and rigidity) that determine the immunological effects of liposomes and other nanoparticles. In chapter 3 we present a detailed study on the effect of the rigidity of anionic liposomes, as measured by atomic force microscopy, on antigen-specific regulatory T-cell (Treg) responses. In chapter 4, we show that our optimized anionic liposomes can induce potent antigen-specific Treg responses, and can be used to delay atherosclerosis progression in a mouse model. Chapter 5 also focuses on liposomal treatment of atherosclerosis, but here targeted liposomes were prepared to successfully deliver a small molecule to foam cells in atherosclerotic plaques. In Chapter 6, we used cationic liposomes in combination with an adjuvant for cancer immunotherapy in mice. Finally, we summarize the overall findings in chapter 7 and discuss perspectives of using liposomes for vaccination and targeted drug delivery. Show less
Atherosclerosis is the main pathology behind most cardiovascular diseases. It is a chronic inflammatory disease characterized by the formation of lipid-rich plaques in arteries. Atherosclerotic... Show moreAtherosclerosis is the main pathology behind most cardiovascular diseases. It is a chronic inflammatory disease characterized by the formation of lipid-rich plaques in arteries. Atherosclerotic plaques are initiated by the deposition of cholesterol-rich LDL particles in the arterial walls leading to the activation of innate and adaptive immune responses. Current treatments focus on the reduction of LDL blood levels using statins, however the critical components of inflammation and autoimmunity have been mostly ignored as therapeutic targets. The restoration of immune tolerance towards atherosclerosis-relevant antigens can arrest lesion development as shown in pre-clinical models. In this review, we evaluate the clinical development of similar strategies for the treatment of inflammatory and autoimmune diseases like rheumatoid arthritis, type 1 diabetes or multiple sclerosis and analyse the potential of tolerogenic vaccines for atherosclerosis and the challenges that need to be overcome to bring this therapy to patients. Show less
Benne, N.; Leboux, R.J.T.; Glandrup, M.; Duijn, J. van; Lozano Vigario, F.; Neustrup, M.A.; ... ; Slütter, B. 2019
Regulatory T cells (Tregs) are vital for maintaining a balanced immune response and their dysfunction is oftenassociated with auto-immune disorders. We have previously shown that antigen-loaded... Show moreRegulatory T cells (Tregs) are vital for maintaining a balanced immune response and their dysfunction is oftenassociated with auto-immune disorders. We have previously shown that antigen-loaded anionic liposomescomposed of phosphatidylcholine (PC) and phosphatidylglycerol (PG) and cholesterol can induce strong antigenspecificTreg responses. We hypothesized that altering the rigidity of these liposomes while maintaining theirsize and surface charge would affect their capability of inducing Treg responses. The rigidity of liposomes isaffected in part by the length and saturation of carbon chains of the phospholipids in the bilayer, and in part bythe presence of cholesterol. We used atomic force microscopy (AFM) to measure the rigidity of anionic OVA323-containing liposomes composed of different types of PC and PG, with or without cholesterol, in a molar ratio of4:1(:2) distearoyl (DS)PC:DSPG (Young's modulus (YM) 3611 ± 1271 kPa), DSPC:DSPG:CHOL(1498 ± 531 kPa), DSPC:dipalmitoyl (DP)PG:CHOL (1208 ± 538), DPPC:DPPG:CHOL (1195 ± 348 kPa),DSPC:dioleoyl (DO)PG:CHOL (825 ± 307 kPa), DOPC:DOPG:CHOL (911 ± 447 kPa), and DOPC:DOPG(494 ± 365 kPa). Next, we assessed if rigidity affects the association of liposomes to bone marrow-deriveddendritic cells (BMDCs) in vitro. Aside from DOPC:DOPG liposomes, we observed a positive correlation betweenliposomal rigidity and cellular association. Finally, we show that rigidity positively correlates with Treg responsesin vitro in murine DCs and in vivo in mice. Our findings underline the suitability of AFM to measureliposome rigidity and the importance of this parameter when designing liposomes as a vaccine delivery system. Show less
