Vaccines recombinant vector

The nasal tissue is highly vascularized and provides efficient systemic absorption. Compared with oral or subcutaneous administration, nasal administration enhances bioavailability and improves safety and efficacy. Chitosan enhances the absorption of proteins and peptide drugs across nasal and intestinal epithelia. Gogev et al. demonstrated that the soluble formulation of glycol chitosan has potential usefulness as an intranasal adjuvant for recombinant viral vector vaccines in cattle [276]. 

Yokoyama, N., Maeda, K., and Mikami, T. 1997. Recombinant viral vector vaccines for veterinary use. Journal... 

Early animal experiments have underlined the potential of vaccinia-based vector vaccines. Vaccinia virus-housing genes from HIV have clearly been found to elicit both humoral and cell-mediated immune responses in monkeys. Similar responses in other animals have been reported when surface polypeptides from a variety of additional pathogens have been expressed in recombinant vaccinia systems (Table 10.16). Human clinical trials are now in progress. 

Imler, J.-L. Adenovirus vectors as recombinant viral vaccines. Vaccine 1995, 13, 1143-1151. 

The ability of two soluble chitosan formulations (chitosan and glycol chitosan) to improve the immunogenicity of an intranasaUy administered replication-defective human adenovirus type 5 expressing BoHV-1 glycoprotein D-based vaccine was investigated in cattle (Vila et al. 2004). It was reported that soluble formulation of glycol chitosan has promising potential use as an intranasal adjuvant for recombinant viral vector vaccines in cattle. 

Most vaccine vectors developed to date are viral based, with poxviruses (as well as picorna viruses and adenoviruses) being used most. In general, such recombinant viral vectors elicit both... 

The use of recombinant viral vectors as vaccination tools displays considerable clinical promise. One potential complicating factor, however, centres around the possibility that previous recipient exposure to the virus being used as a vector would negate the therapeutic efficacy of the product. Such prior exposure would likely indicate the presence of circulating immune memory... 

Yeast expression vectors have been among those most commonly used since the beginning of gene technology. Vectors based on baker s yeast, Saccharomyces cerevisiae, have been especially popular for robust expression of many types of recombinant proteins [90]. For instance, the first commercially available recombinant vaccine, the hepatitis B surface antigen vaccine, was produced from an S. cerevisiae vector [91]. Many other recombinant proteins have also been efficiently expressed in yeast including al-Antitrypsin [92], insulin [93], Epstein-Barr virus envelope protein [94], superoxide dismutase [95] and interferon-a [90]. 

Advances in genomics, molecular biology, and recombinant technology have provided new directions for the discovery, development, and manufacture of vaccines. One of the current approaches is a minimalist strategy to decouple the virulence and immunity functions. The aim is to use only the immunity part to confer protection, so that the vaccine is safe to be administered. The approach can be divided into subunit, vector-based, DNA, and peptide vaccines. 

J. Kuball, M. Schnler, E. Antunes-Ferreira, W. Herr, M. Neumann, E. Obenaner-Kntner, E. Westreich, C. Huber, T. Wolfel, and M. Theobald, Generating p53-specific cytotoxic T lymphocytes by recombinant adenoviral vector based vaccination in mice bnt not man. Gene Therapy, 833-843 (2002). 

Several HIV vaccine systems based upon live vectors have also been developed, in an attempt to stimulate a significant T cell as well as B cell immune response. Both envelope and core antigens have been expressed in a number of recombinant viral systems, most notably in vaccinia. The clinical efficacy of these remain to be established. 

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