Genetically altered bacteria tests stir ire Officials of Advanced Genetic Sciences, of Oakland, Calif., cannot seem to figure out that environmental release of genetically engineered organisms is a very sensitive issue. Recent press reports reveal that AGS performed outdoor plant pathogenicity tests with genetically altered bacteria for several months in early 1985. Bacteria were injected into six varieties of dormant fruit trees growing in pots on the roof of the company's facility. John Bedbrook, AGS vice president and research director, tells C&EN that because the bacteria were injected into the 48 trees rather than sprayed onto them, the experiments did not constitute an environmental release. The trees were closely monitored during the test, Bedbrook says, and after the test, the inoculated branches were removed and sterilized. "In conducting these tests, AGS believed it adhered to all available guidelines and took necessary precautions to ensure environmental safety," Bedbrook says. The Environmental Protection Agency disagrees with the company. The agency states: "EPA believes that the tree injections did constitute an environmental release experiment that should have been brought to the agency's attention before the experiment was begun." However, the statement goes on: "The experiment involves the same bacteria that the agency later reviewed and approved for release in an open field because of the low probability of any adverse effects." EPA says it is continuing its investigation of the incident, but so far has not revoked AGS's field test permit. The experiments involve altered Pseudomonas syringae and Pseudomonas fluorescens bacteria. Both bacteria secrete a protein that allows them to act as nuclei in frost formation. AGS scientists use recombinant DNA techniques to delete a portion of the gene to produce so-called "ice nucleation activity minus (INA - )" bacteria that can be used to protect plants from frost damage. In early February, a proposed AGS field test of INA~ bacteria, which
was to be conducted near Salinas, Calif., was blocked by the Monterey County Board of Supervisors. The experiment had been approved by EPA and the California Department of Food & Agriculture. But AGS neglected to tell anybody in Monterey County about the test and many citizens were outraged. The most recent incident is an-
other public relations disaster for AGS and a bonanza for biotechnology critics. A spokesman for Jeremy Rifkin's Foundation on Economic Trends, probably the most active organization opposing biotechnology experimentation, says the AGS injection experiment "makes a sham of the regulatory process and is a violation of the public trust." •
Synthetic peptide produces hepatitis antibodies Antibodies to a synthetic peptide corresponding to a small portion of a hepatitis B virus envelope protein neutralize live hepatitis B virus, according to scientists at the New York Blood Center and California Institute of Technology. The research suggests that a simple peptide could form the basis for a more effective and less expensive vaccine against hepatitis B than those now available. The researchers were led by A. Robert Neurath of the blood center and Stephen B. H. Kent of Caltech's division of biology. The discovery is an outgrowth of several years of research on the immune response to hepatitis B virus, Kent says. The findings were published in the March issue of Vaccine. Most efforts to develop a hepatitis B vaccine have focused on what is known as the S protein of the virus. Until recently, the S protein, which contains 226 amino acids, was thought to be the sole constituent of the hepatitis B virus envelope. However, the gene that codes for the hepatitis B envelope protein contains an open reading frame of 1200 nucleotides, sufficient to code for a protein containing 400 amino acids. Over the past three years, researchers have discovered that, in fact, there are three envelope proteins: the S protein, an M protein that contains an additional 55 amino acids, and an L protein that contains all 400 possible amino acids. The "extra" 55 amino acids in the M protein are called preS2; the additional 119 amino acids in the L protein are called preSl. The two regions are known collectively as preS. The research team has studied different sections of preSl and preS2 to determine their antigenic properties. The recently reported re-
search focuses on the 26-amino-acid segment at the amino terminal end of the preS2 region. The scientists used the preS2derived peptide to produce antibodies in rabbits. The antibodies were isolated and mixed with live hepatitis B virus, and the mixture was administered to chimpanzees at the New York Blood Center's laboratory at Liberian Institute for Biomedical Research in Africa. The chimpanzees did not develop hepatitis B, as they would have if the virus had remained infectious. "This is the first experimental proof that a neutralizing immune response is being coded for by the preS region," Kent says. Hepatitis B vaccines based solely on the S protein, such as the currently available Heptavax vaccine produced by Merck, Sharp & Dohme, are effective for about 85% of the general population, Kent says. However, such vaccines are much less effective for newborn infants. In regions where the disease is endemic, a common route of transmission of hepatitis B is from mother to newborn, so a vaccine effective in newborns is important if hepatitis is eventually to be eliminated. There is evidence that vaccines containing the preS region are significantly more effective in newborns as well as evidence that the preS region enhances the immune response to the S protein, Kent explains. The research also holds promise for vaccines made by chemical synthesis of peptides or recombinant DNA production of peptides rather than by inactivation of live virus. Current hepatitis B vaccines are produced by inactivation. Such synthetic vaccines could be safer and less expensive than traditional vaccines. • March 3, 1986 C&EN
5
