Targeting pathogen recognition receptors on dendritic cells (DCs) offers the advantage of triggering specific signaling pathways to induce a tailored and robust immune response. In this work, we describe a novel approach to targeted antigen delivery by decorating the surface of polyanhydride nanoparticles with specific carbohydrates to provide "pathogen-like" properties that ensure nanoparticles engage C-type lectin receptors on DCs. The surface of polyanhydride nanoparticles was functionalized by covalent linkage of dimannose and lactose residues using an amine-carboxylic acid coupling reaction. Coculture of functionalized nanoparticles with bone marrow-derived DCs significantly increased cell surface expression of MHC II, the T cell costimulatory molecules CD86 and CD40, the C-type lectin receptor CIRE and the mannose receptor CD206 over the nonfunctionalized nanoparticles. Both nonfunctionalized and functionalized nanoparticles were efficiently internalized by DCs, indicating that internalization of functionalized nanoparticles was necessary but not sufficient to activate DCs. Blocking the mannose and CIRE receptors prior to the addition of functionalized nanoparticles to the culture inhibited the increased surface expression of MHC II, CD40 and CD86. Together, these data indicate that engagement of CIRE and the mannose receptor is a key mechanism by which functionalized nanoparticles activate DCs. These studies provide valuable insights into the rational design of targeted nanovaccine platforms to induce robust immune responses and improve vaccine efficacy. The use of vaccine adjuvants to activate the innate immune system is crucial to vaccine effectiveness. 1 Adjuvants can be used to enhance the efficacy of single dose vaccines and reduce the required antigen dose. The use of biodegradable polymer nanoparticles as vaccine delivery vehicles allows for effective delivery of payloads by parental or mucosal administration by protecting the antigen from harsh physiological conditions and enabling transport across biological barriers (e.g., mucus membranes). 2 Polyanhydride nanoparticles have shown excellent potential as vaccine carriers. 3À6 Encapsulation of protein antigens into polyanhydride particles stabilizes them and provides sustained azntigen release; 4,7 these particles also enhance the immune response by acting as an adjuvant. 3 Dendritic cells (DCs) are antigen presenting cells (APCs) that play a major role in connecting the innate and adaptive immune systems, a key step to inducing protective immunity. 8 DCs can sense and internalize antigen by a variety of mechanisms that trigger DC maturation and direct further interactions with other immune cells, including naive T cells. 1,9,10 Pattern recognition receptors (PRRs) on DCs detect the presence of a potential threat by interacting with pathogen-associated molecular patterns (PAMPs). 10,11 In particular, C-type lectin receptors (CLRs) are PRRs with highly conserved carbohydrate-recognition domains that bind sugar moieties (e.g., mannose, fuco...

Mycobacterium tuberculosis and the protozoan parasites of the genus Leishmania are intracellular pathogens that can survive in macrophages—the very white blood cells of the immune system responsible for engulfing and ultimately clearing foreign invaders. The ability of these pathogens to hide within immune cells has made the design of effective therapies, including vaccines, to control tuberculosis and leishmaniasis particularly challenging. Herein we present the synthesis and development of carbohydrate-based probes to demonstrate that only changes in pathogen-associated surface oligosaccharides are sufficient to change cellular immune responses and thereby let a pathogen hide from immune surveillance.

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Microarray techniques based on covalent and noncovalent compound immobilization have been developed for screening proteins, antibodies and enzymes to probe the possible biological roles of these interactions as well as their therapeutic and diagnostic potential. Small-molecule microarrays are particularly valuable for creating and probing multivalent displays of molecules, such as saccharides that mimic the multivalent displays of cell surface-bound compounds. After development of the method for the screening of carbohydrates in a multivalent display format, microarrays based on noncovalent fluorous interactions have seen use in probing protein-binding partners with a range of arrayed compounds. In this article, existing strategies and future perspectives for fluorous-based small-molecule microarrays for protein, antibody and enzyme screening will be presented. To date, qualitative and quantitative fluorous-based microarrays have offered important information regarding biomolecular interactions. Larger compound arrays created with automated fluorous-based synthesis and diagnostic tools based on fluorous-based microarrays are likely ahead.