Silicon Investor (SI) -- The First Internet Community

STOCKTALK

We've detected that you're using an ad content blocking browser plug-in or feature. Ads provide a critical source of revenue to the continued operation of Silicon Investor. We ask that you disable ad blocking while on Silicon Investor in the best interests of our community. If you are not using an ad blocker but are still receiving this message, make sure your browser's tracking protection is set to the 'standard' level.

Biotech / Medical : progenics -- Ignore unavailable to you. Want to Upgrade?

To: tuck who wrote (67)	10/1/2002 10:39:41 AM
From: keokalani'nui	Read Replies (1) \| Respond to of 139

Progenics Reports Progress in Developing a New Class of AIDS Vaccines Publications Cite Use of Stable HIV Surface-Protein Configurations to Develop Prophylactic Vaccines Tuesday October 1, 5:00 am ET TARRYTOWN, N.Y.--(BUSINESS WIRE)--Oct. 1, 2002--Progenics Pharmaceuticals, Inc. (Nasdaq: PGNX - News) announced the development of vaccine candidates that contain critical surface proteins whose form closely mimics the structures found on the virus. Until now, the instability of these surface "spikes" has hampered efforts to produce an effective prophylactic vaccine. The new vaccine components are designed to elicit an immune response capable of neutralizing the human immunodeficiency virus (HIV), the virus that causes AIDS, before it can establish infection. The findings were described in two recent articles in the Journal of Virology. "Our new vaccine candidates are the culmination of several years of effort to first determine, and then mimic as closely as possible, the native form of the HIV envelope spike - the glycoproteins which protrude from the virus," said John P. Moore, Ph.D., Professor of Microbiology and Immunology at the Weill Medical College of Cornell University, and senior author of the Journal of Virology publications. "The rationally designed envelope trimers described in these studies more faithfully resemble the structures on the virus surface than proteins that have been made previously, so they may prove to be more effective vaccine candidates." "The production of stable envelope trimers represents an important step towards our goal of developing a vaccine that protects individuals from becoming infected with the virus," said Paul J. Maddon, M.D., Ph.D., Progenics' Chairman and CEO. "We have begun testing these trimeric constructs in animals to determine their ability to elicit antibodies capable of neutralizing naturally occurring strains of HIV. Success in the animal studies would support advancement of our vaccine candidates into human clinical trials." Prophylactic HIV vaccines, which are under development by companies and academic laboratories worldwide, are designed to work by eliciting antibodies that target viral surface proteins and neutralize the virus. The surface of HIV is studded with envelope spikes that consist of three copies each of the gp120 and gp41 glycoproteins in a trimeric configuration. These envelope trimers mediate entry of the virus into immune system cells. Blocking this viral-entry process thus impedes infection. However, the instability of the natural form of the timer complex in the laboratory has been a major obstacle to the creation of a vaccine, as the dissociated components, monomeric gp120 and gp41, do not reliably elicit antibodies that neutralize circulating strains of HIV. The Journal of Virology papers co-authored by researchers at Progenics and Cornell (76(15) 7760-7776 and 76(17) 8875-8889) describe two novel strategies for producing the stabilized gp120/gp41 proteins in their native trimeric form. The first approach involved modifying the gp120 glycoprotein to enhance trimer stability, whereas the second method employed modifications to gp41. Importantly, the trimers can be isolated in homogenous form, as required for use in a vaccine. The collaborating scientists believe that a vaccine containing the trimeric structure of HIV surface proteins may be crucial to eliciting a immune response able to neutralize the virus in humans. "An effective HIV vaccine offers the greatest potential for stemming the worldwide spread of AIDS," said Dennis R. Burton, Ph.D., Professor of Immunology at The Scripps Research Institute in La Jolla, CA, and a leading expert in the area of HIV vaccine research. "Vaccines against other viruses work by generating antibodies that bind the surface of the virus, thereby rendering it non-infectious. However, such neutralizing antibodies to HIV have been difficult to induce with vaccines currently in development. The new viral envelope trimers represent very interesting leads for HIV vaccine development."