The development of an effective anti-HIV topical microbicide, especially a female-controlled, vaginal microbicide, has been deemed an urgent global priority by numerous international agencies, including the World Health Organization, the U.S. Department of Health and Human Services, the National Institute of Allergy and Infectious Diseases, and others. The present invention provides antiviral proteins (collectively referred to as cyanovirins), conjugates thereof, DNA sequences encoding such agents, host cells containing such DNA sequences, antibodies directed to such agents, compositions comprising such agents, and methods of obtaining and using such agents for the production of microbicides.
Cyanovirin-N (CV-N) potently and irreversibly inactivates diverse primary strains of HIV-1, including M-tropic forms involved in sexual transmission of HIV, as well as T-tropic and dual-tropic forms; CV-N also blocks cell-to-cell transmission of HIV infection. CV-N is directly virucidal, interacting in an unusual manner with the viral envelope, apparently binding with extremely high affinity to poorly immunogenic epitopes on gp120. Further, cyanovirin-N (CV-N) and homologous proteins and peptides potently inhibit diverse isolates of influenza viruses A and B, the two major types of influenza virus that infect humans.
The described technology includes glycosylation-resistant mutants of CV-N, which code sequences to enable ultra large-scale recombinant production of functional cyanovirins in non-bacterial (yeast or insect) host cells or in transgenic animals or plants. Therefore, these glycosylation-resistant mutants may allow industry to produce CV-Ns on a large scale and make CV-Ns cheap enough for developing countries to benefit from this invention.
CV-N was benign in vivo when tested in the rabbit vaginal toxicity/irritancy model, and was not cytotoxic in vitro against human immune cells and lactobacilli (unpublished). CV-N is readily soluble in aqueous media, is remarkably resistant to physicochemical degradation and is amenable to very large-scale production by a variety of genetic engineering approaches. 0