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Molecular Targets Development Program

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Cyanovirin-N in the News Again

An award has been assigned to the Poster Presentation "Mucosal Delivery of Microbicides by Commensal Bacteria" illustrating results of a research project in collaboration between the MTDP (NCI, CCR) and the Dep. of Molecular Biology of the University of Siena, Italy. The award has been handed over to the poster authors personally by the Princess Royal during the official ceremony at the Microbicides 2004 Conference that has taken place in London (28-31 March 2004). 764 delegates from 52 countries attended the conference, which has reported novel and innovative works in the microbicides field and provided opportunities for knowledge sharing between microbicide researchers and public-health organizations.

The global HIV/AIDS epidemic killed more than 3 million people in 2003, and an estimated 5 million acquired the human immunodeficiency virus (HIV)-bringing to 40 million the number of people living with the virus around the world (AIDS Epidemic Update 2003). About 2/3 of infected people live in sub-Saharan Africa and 58% of them are women. Sexual contact is the main way by which HIV is transmitted and heterosexual transmission accounts for at least 75% or more of all HIV infections. In this context, with the knowledge that an effective HIV vaccine is still not yet in sight in the near term, there is a growing interest in the development of topical microbicides capable of preventing sexual transmission of HIV.

Cyanovirin-N (CV-N), a potent HIV-inactivating protein, was originally discovered from the cyanobacterium (blue-green alga) Nostoc ellipsosporum in the previous incarnation of the MTDP at the NCI [1]. It has been demonstrated that CV-N gel as a topical microbicide can prevent rectal and vaginal transmission of a pathogenic chimeric SIV/HIV-1 virus (SHIV) in macaques without cytotoxic or clinical adverse effects [2, 3]. These studies encourage clinical evaluation of CV-N as a topical microbicide to prevent sexual transmisision of HIV in humans.

An effective CV-N-based microbicide may require long-term presence or continuous delivery of CV-N at the potential mucosal sites of entry of HIV. One approach to this need is the endogenous production of virucidal concentrations of CV-N at mucosal surfaces by a colonizing commensal bacterium [4]. The Poster Presentation illustrated the feasibility to express CV-N in the commensal bacterium Streptococcus gordonii in a recombinant form that was active as the native protein, and the development of a genetic system to stably express CV-N and other microbicides in different Lactobacillus strains, which are suitable for long-term vaginal colonization.

Antimicrob. Agents Chemother. 41: 1521-30 (1997)
AIDS Res. Hum. Retroviruses. 19: 535-41 (2003)
AIDS Res. Hum. Retroviruses. 20: 11-8 (2004)
AIDS. 16: 1351-6 (2002)

This page was last updated on 2/4/2008.