Antigen delivery

These results open the exciting possibility of using degradable, tyrosine-derived polymers as "custom-designed" antigen delivery devices. On the other hand, our results indicate that the immunological properties of tyrosine-derived polymers will have to be carefully evaluated before such polymers can be considered for use as drug delivery systems or medical implants. 

In vivo reproducible results can only be achieved if the liposome-drug or -antigen combinations are thoroughly characterized upon preparation in terms of their physical and chemical properties and, besides, if the stability during storage is ensured. In this chapter both the pharmaceutical (preparation, characterization, and stability) aspects and the therapeutic potentials and limitations of drug and antigen delivery with liposomes will be discussed. 

Thus, liposomes—with or without adjuvants—have a potential as antigen delivery systems. No clear insights exist on how to prepare liposome-based vaccines with optimum immunological properties by rationale instead of by trial and error. Therefore, much basic work is needed to unravel the mechanisms involved. 

E. C. (1988b). Incorporation of the major outer membrane protein of Neisseria gonorrhoeae in saponin-Upid complexes (Iscoms) Chemical analysis, some structural features, and comparison of their immunogenicity with three other antigen delivery systems, Inf. Immun., 56, 432-438. 

Polymeric Nanoparticles for Antigen Delivery and Adjuvant 3.1 Preparation of Antigen-Loaded Nanoparticles... 

It has also been reported that antigen delivery to DCs via PLGA particles increased the amount of protein that escaped from endosomes into the cytoplasm. How proteins or peptides encapsulated within PLGA particles become accessible to the cytoplasm is still not clear. It is suggested that the gradual acidification of endosomes leads to protonation of the PLGA polymer, resulting in enhanced hydrophobicity and attachment and rupture of the endosomal membrane [147]. 

Tamber H, Johansen P, Merkle HP et al (2005) Formulation aspects of biodegradable polymeric microspheres for antigen delivery. Adv Drug Deliv Rev 57 357-376... 

O Hagan DT (1998) Recent advances in immunological adjuvants the development of particulate antigen delivery systems. Exp Opin Invest Drugs 7 349-359... 

Stomi T, Kundig TM, Senti G et al (2005) Immunity in response to particulate antigen-delivery systems. Adv Drug Deliv Rev 57 333-355... 

Wang X, Uto T, Akagi T et al (2008) Poly(y-glutamic Acid) nanoparticles as an efficient antigen delivery and adjuvant system potential for an anti-AIDS vaccine. J Med Virol 80 11-19... 

Ohagan, D.T. et al., Biodegradable Microparticles as Controlled Release Antigen Delivery Systems, Immunology. 73, 239, 1991. 

Mestecky, J., Michalek, S. M., Moldoveanu, Z., and Russell, M. W. (1997). Routes of immunization and antigen delivery systems for optimal mucosal immune responses in humans. Behring Inst. Mitt. 98, 33-43. 

Dileo J, et al. Lipid-protamine-DNA-mediated antigen delivery to antigen presenting cells results in enhanced anti-tumor immune responses. Mol Ther 2003 7 640. 

Bungener DT, Huckriede A, Wilschut J. Virosomes as an antigen delivery system. J Liposome Res 2000 10 329-338. 

It is of particular clinical relevance to test the effects of mucosal allergen application in already sensitized organisms. The obvious advantage of the use of so-called hypoallergenic molecules lies in their risk-free application. Thus, the practical consequences from such experimental studies could include the development of low-risk mucosal vaccines based on the induction of tolerance - with or without the use of certain mucosal antigen delivery systems. 

Babiuk, S., et al. 2000. Cutaneous vaccination The skin as an immunologically active tissue and the challenge of antigen delivery. J Control Release 66 199. 

OHagan, D.T., D. Rafferty, S. Wharton, and L. Ilium. 1993. Intravaginal immunization in sheep using a bioadhesive microsphere antigen delivery system. Vaccine 11 660. 

Antigen delivery through liposomes, hollow membrane-bound spheres, can be achieved by entrapping the molecule in the lipid membrane or inside the hollow cavity. Modified liposomes have been able to induce mucosal IgA responses compared to free antigen (Ann Clark et al. 2001 Aziz et al. 2007). Liposomes containing pertussis toxin (Guzman et al. 1993), Streptococcus mutans (Childers et al. 2002), or bovine serum albumin (Therien et al. 1990) as vaccine antigens have been tested in experimental models and induced effective antibody- and cell-mediated immune responses. 

However, in general, only low levels of antibodies have been induced by intravaginal immunizations and the antibodies generated have been predominantly localized in the genital tract, even in the presence of potent antigen delivery systems. 

Keywords. Nanoparticle, Water-soluble polymers, Hydrophilic drugs, Protein delivery, Drug delivery, Antigen delivery, Processing, Permeability control... 

Data presented in this review also address a bio availability issue, in vivo antigen delivery. Bioavailability measures how much of the drug molecule arrives at its site of action compared with how much is in the formulation delivered to the... 

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