British Bio-technology Group plc (BBL) of Oxford, England,announced Monday that the National Institute for Allergy andInfectious Diseases (NIAID) will sponsor U.S. trials on theBritish company's AIDS treatment vaccine, p24-VLP.
The trials of this vaccine, which is designed to slow down orprevent the progression of HIV-positive patients to AIDS,should begin in 1993, the company said.
The vaccine, p24-VLP, is a genetically engineered productdesigned to stimulate immunity to the HIV core protein p24.Studies have shown that patients who have a high immunity top24 progress more slowly to full-blown AIDS than patientswith a low immune response.
This is the only candidate AIDS vaccine that specifically targetsthe virus' core proteins, Peter Lewis, BBL 's director of R&D,told BioWorld. The most similar type of vaccine that elicits animmune response is denatured HIV whole virus, which is"essentially the viral core," Lewis said. "There are no othergenetically engineered core vaccines around."
In fact, Lewis said that the NIAID is particularly interested inp24-VLP because it is a core vaccine; NIAID has "taken on"most of the vaccines that are based on viral envelope proteins,he said.
The VLPs consist of spherical subcellular particles formed by aself-assembling yeast protein, TY, spliced to the p24 antigen.Each spherical particle can contain up to 300 copies of theTY/p24 spliced molecule. This particle is so large, Lewis said,that it's like an adjuvant all on its own. "Evidence shows that ifyou put an engineered protein into a yeast particle that self-assembles, you can get a much stronger immune response,"Lewis said.
And for HIV, he explained, "the core of HIV seems to self-assemble in the same way as this yeast protein does, so (thep24-VLP vaccine) is more truly a mimic of this virus."
Moreover, as BBL found in its British Phase I trials on healthyHIV-negative males, p24-VLP stimulates both antibody andcellular immune responses to HIV. "VLPs seem to beparticularly good at stimulating cellular immunity," Lewis toldBioWorld. If this observation pans out as a general finding, thiswould make BBL's VLP technology an "attractive candidate" forvaccine development, Lewis said.
In fact, the NIH has granted $300,000 to BBL to continuefundamental work on VLP vaccine technology in other viraldiseases.
-- Jennifer Van Brunt Senior Editor
(c) 1997 American Health Consultants. All rights reserved.