NBIAP NEWS REPORT May 1, 1993 BIOTECHNOLOGY RISK ASSESSMENT RESEARCH GRANTS PROGRAM; FISCAL YEAR 1993; SOLICITATION OF RESEARCH PROPOSALS Announcement of solicitation of applications and guidelines for submitting research proposals under the 1993 Biotechnology Risk Assessment Research Grants Program was published in the Federal Register, Vol. 58, No. 70, Wednesday, April 14, 1993. Total available funding for 1993 for support of the Program is $1,700,000. Under the Program, USDA will competitively award research grants to support science-based biotechnology regulation and thus help address concerns about the effects of introducing genetically modified organisms into the environment and to help regulators develop policies concerning such introduction. Proposals are invited in the areas of (1) biotechnology risk assessment research as appropriate to agricultural plants, animals and microbes, and (2) the organization of an annual conference of funded researchers to help communicate research needs, findings, and emerging opportunities. Proposals will be evaluated by a peer panel of scientists for among other things, science quality; relevance for current regulatory issues; and intent to advance the safe application of biotechnology to agriculture by providing new knowledge for science based regulatory decisions. The development of better methods for field testing genetically modified organisms will also be considered. Proposals submitted through the regular mail must be received by June 14, 1993. Hand delivered proposals must be submitted by June 14, 1993 to an express mail or courier service or brought to the Awards Management Division of the USDA in Washington, D.C. The complete Federal Register Announcement can be viewed or downloaded from this Bulletin Board in Door #2. Copies of the Federal Register Announcement can also be obtained by contacting: Dr. David MacKenzie; Cooperative State Research Service; U.S. Department of Agriculture; Suite 330, Aerospace Center; Washington, D.C. 20250-2220. Telephone: 202-401-4892; Fax: 202-401-4888 WORKSHOP ON FIELD TESTING HELD FOR IBCs AND STATE BIOTECH REGULATORS Patricia L. Traynor, Ph.D., Michigan State University The first NBIAP workshop on field testing, held April 15 - 16 at Michigan State University, gave IBC representatives and state regulators an opportunity to learn how and why federal regulations apply to environmental releases of genetically modified organisms. Participants gained a better understanding of the legal requirements and the constraints imposed upon regulatory agencies by existing laws, particularly the National Environmental Policy Act. Workshop participants also benefitted from the opportunity to hear how other IBC's and state regulatory agencies operate. Invited speakers were Arnold Foudin (Deputy Director for Permits, APHIS/BBEP), William Witt (Director of Veterinary Services, FDA and member of the ABRAC), Bob Frederick (Biotechnology Research Coordinator, EPA/ORD), Dave MacKenzie (Director of the National Biological Impact Assessment Program), Scott Shore (North Carolina Department of Agriculture), and Peter Palukaitis (Cornell University). Although the APHIS' notification procedure does not delegate responsibility to IBC's for overseeing field tests, as was originally proposed, local committees still have a significant role to play. The lack of Federal oversight of contained research (in laboratories and greenhouses) places responsibility on local IBC's to review protocols, determine what the risks are, and consider what mitigating measures would be appropriate in the event of an inadvertent release. In field tests, transgenic plants or microorganisms that are eligible to be tested under the notification procedure are still regulated articles. IBC's have a responsibility to know what experiments are being done, and to make sure that specified performance standards are being met. In future accidental or intentional releases that result in litigation, the courts are expected to look very closely at the actions of the IBC. A second role for IBC's is to provide information. The IBC needs to ensure that the institution's administration and the state authorities know what release experiments are planned or underway. Additionally, these committees can serve as the informed group that interacts with the community and addresses public concerns. Based on the very positive response from both participants and speakers, NBIAP's Information Systems for Biotechnology project is planning similar programs in other regions of the country. The next workshop will be held in the southeast later this summer. For more information, contact Dr. Patricia L. Traynor at (517) 336-3923. REGULATORY UPDATE FDA SEEKS ADDITIONAL COMMENT ON LABELING ISSUES ARISING FROM GENETICALLY ENGINEERED FOODS In the April 28 issue of the Federal Register, Vol. 58, No. 80, pp 25837 - 25843, the Food and Drug Administration announced a request for data and information on certain labeling issues pertaining to public comments associated with the Agency's Statement of Policy (published in Federal Register on May 29, 1992) of Food Derived from New Plant Varieties; Including Genetically Modified Plants. This request will provide an opportunity for interested persons to present data and other information concerning how foods derived from genetically engineered plants should be labeled. Because the issue raises complex scientific and legal questions, FDA intends to evaluate the information received in response to this announcement to identify specific issues to be discussed at a public forum to be announced in a future issue of the Federal Register. The FDA also intends to seek input from the scientific community on the question of the potential for food allergy raised by foods derived from new plant varieties. These two issues together with questions about the need for premarket notification to the FDA, and Agency approval of all new plant varieties developed through genetic engineering plus appropriate testing of foods derived from genetically engineered plants were indicated as a source of concern in a significant percentage of the more than 3,000 public comments submitted to FDA on its Statement of Policy Concerning Foods Derived from New Plant Varieties. The Federal Food, Drug and Cosmetic Act gives FDA the authority to regulate the labeling of foods. Historically, the FDA has held that the method of development of a new plant variety is not material information under the Act and no labeling is required. In the May 1992 Statement, this principle was applied to plants developed via genetic engineering. While most of the comments received on the Policy Statement raised the issue of labeling foods from genetically engineered plants, they did not define "genetic engineering" or discuss the characteristics that would distinguish a food from a genetically engineered plant from another food and thus might warrant labeling. FDA is soliciting additional data and information to further define "genetic engineering" as used in the comments received by the Agency; to clarify under what circumstances such labeling is believed to be necessary; to address how foods derived from "genetically engineered" plants differ from plants developed by other methods of plant breeding; and to specify how such labeling, if required, would be accomplished as a practical matter. Written comments, which must be received by July 27, 1993, should be submitted to the Dockets Management Branch (HFA-305), Food and Drug Administration, Room 1-23, 12420 Parklawn Drive, Rockville, Md. 20857. For further information contact: James Maryanski, Center for Food Safety and Applied Nutrition (HFS-13), Food and Drug Administration, 200 C Street, SW, Washington, DC 20204. Telephone: 202-205-4359. The complete text of this Federal Register Announcement will be available on this Bulletin Board. NOTIFICATION PROCEDURE FOR FIELD TESTS GOES INTO EFFECT On April 30, the Amendments to the Regulations to permit the use of a notification procedure rather than permits for field tests of certain crop plants with which the USDA's Animal and Plant Health Inspection Service (APHIS) has had experience (corn, cotton, potato, soybean, tobacco and tomato) went into effect. Henceforth, researchers may conduct field tests with the specified genetically modified crop plants provided they notify APHIS 30 days in advance of the planned test and meet other eligibility and performance standards set forth in the final rule. New rules governing the petition for nonregulated status (the process for conducting large scale testing of genetically modified organisms leading to commercialization) also took effect on April 30. Fur further information about the notification procedure and the petition for a determination of non-regulated status, contact: Terry J. Medley; Director Biotechnology, Biologics, and Environmental Protection; Animal and Plant Health Inspection Service; U.S. Department of Agriculture; Room 850, Federal Building; 6505 Belcrest Road; Hyattsville, MD 20782. Telephone: 301-436-4602 The complete text of the Final Rule is available for downloading from the Bulletin Board in Door #1. ENVIRONMENTAL ASSESSMENT OF THE FINAL RULE To comply with the requirements of the National Environmental Policy Act (NEPA), APHIS prepared a special assessment which has lead to a finding of no significant impact with respect to the amendments to the regulation which will substitute a notification procedure for permits in certain circumstances and establishes a petition process for the determination of nonregulated status. The finding of no significant impact is based on the following factors: 1. There is no impact from issuance of procedural regulations for applicants to petition APHIS regarding determinations of regulated status for particular transgenic plants. The point of commitment for any such petition will occur when APHIS acts on that petition. 2. Interstate movement and importation of regulated articles under notification will involve movement of familiar materials from confined conditions into inspected, confined facilities where they will not be treated significantly differently from articles under permit. 3. There is no potential for plants tested under notification to cause disease. 4. There is no potential for significant impacts of plants tested under notification on nontarget organisms, including organisms beneficial to agriculture. 5. The potential that field testing of plants under notification will lead to the introduction or expansion of weed populations is negligible. 6. Field testing of plants under notification will have no effects on other agricultural commodities. 7. Field testing of plants under notification will have no effects on existing agricultural practices. 8. Field testing of plants under notification will have no impacts on human health. CONGRESSIONAL HEARINGS ON AGRICULTURAL BIOTECHNOLOGY AND FOOD SAFETY On April 20, 1993, the Subcommittee on Agriculture, Rural Development, the Food and Drug Administration and related agencies of the Committee on Appropriations of the House of Representatives, under the chairmanship of Representative Richard Durbin (D-Illinois) held hearings on biotechnology programs at the Department of Agriculture and the Food and Drug Administration. Characterized by Chairman Durbin as a learning experience, the subcommittee members heard statements from Dr. David Kessler, Commissioner of the Food and Drug Administration, Dr. R. Dean Plowman, Administrator of the Agricultural Research Service (USDA), Mr. Terry F. Medley, Acting Associate Administrator, Animal and Plant Health Inspection Service (USDA), and Dr. John Patrick Jordan, Administrator, Cooperative State Research Service (USDA). In his statement, Dr. Kessler explained the views of the FDA about regulating human foods and animal feeds produced from new plant varieties, including crops developed by the newest methods of molecular and cell biology and those developed using traditional techniques as embodied in the FDA's May 29, 1992 "Statement of Policy: Foods Derived from New Plant Varieties." He reiterated that the policy is designed to ensure that (1) new substances introduced into foods are safe for consumption; (2) there are no unintended or unexpected changes in food, such as higher levels of natural toxins; (3) there are no unacceptable changes in nutrients; (4) the potential for introduced proteins to cause allergic reactions must be analyzed. Dr. Kessler also explored the complexities of labeling foods derived from genetically modified plants and announced that FDA would be seeking additional public comments on this important issue. He also said that FDA would be looking further at the question of pre-market notification and the concern about allergenicity of new foods. In his statement Dr. Plowman of the ARS pointed out that biotechnology is not a research program in itself within ARS, but is a component of nearly all ARS research programs. He estimated that in 1993, $114 million of ARS resources will be dedicated to producing improved plants, animals and new products. ARS is working closely with industry to transfer new knowledge and technologies to the private sector for further development and commercialization. Individual ARS scientists explained their work with tissue culture, monoclonal antibodies, DNA probes, recombinant DNA, gene mapping, and gene transfer. Mr. Terry Medley, Acting Associate Administrator of APHIS outlined the Service's authority and programs to regulate veterinary biologics, including those produced from biotechnological processes under the Virus, Serum and Toxin Act of 1913; and for the importation, interstate movement and release into the environment of certain genetically engineered plants and microorganisms under the Plant Pest Act. Since regulations became effective in 1987 he reported that APHIS had issued in excess of 370 permits for field tests at over 724 sites in 35 states and Puerto Rico, and over 1,000 permits for movement. Mr. Medley also explained the provisions of the April 30, 1993 amendment to the regulations that will allow a notification alternative to the permit process in certain circumstances and a petition for determination of nonregulated status. Cooperative State Research Service (CSRS) Administrator, Dr. Jordan, estimated that in 1992, about $74 million was invested in agricultural and environmental biotechnology to improve scientific knowledge, provide new products and processes, increase science capability, foster safe research and coordinate biotechnology activities. This investment was 17% of the Service's overall 1992 budget. For example, under the National Research Initiative (NRI) Competitive Grants Program, some $38.2 million was spent to support biotechnology research in plants, animals and microbes with emphasis on genomic mapping of plant and animal species. CSRS also has established the National Biological Impact Assessment Program (NBIAP) to facilitate the safe field testing of genetically modified organisms. NBIAP has created an information resource for scientists which includes, among other things, an Electronic Bulletin Board with a News Report and databases, software for preparing applications for safe field tests, and a biomonitoring database of environmental releases of genetically modified organisms. CSRS also co-sponsors the Biotechnology Risk Assessment Research Grants Program (see lead article). Dr. Jordan also explained how biotechnology activities were coordinated at USDA and the Office of Agricultural Biotechnology's role in this coordination as well as the Committee on Biotechnology (CBA), the Biotechnology Council and the Agricultural Biotechnology Research Advisory Committee (ABRAC). During the question period, Subcommittee members focused strongly on food safety issues, stating that the public needs assurance about the safety of biotechnologically derived foods. Was the Flavr-Savr tomato safe? Is milk from cows injected with Bovine Growth Hormone (BGH) safe? Is BGH needed at all? Was the patchwork of biotechnology regulations adequate? What about the changes in regulations, i.e. FDA's Food Policy Statement, the APHIS notification procedure; are these signs of deregulation? These questions elicited comments from Dr. Kessler and Mr. Medley that these policies do not represent deregulation but are clarifications and adjustments to regulations that will make them more effective and less burdensome. The Subcommittee also wondered if the U.S. is taking advantage of research to turn out new products and if there is a balance between basic and applied research. Dr. Plowman of ARS responded that ARS research is problem-oriented even though some of it might be characterized as basic. It is directed to achieving greater efficiency of production. In closing, Chairman Durbin stated that the hearing had been very helpful and informative for the members and they now had a better understanding of biotechnology and the issues surrounding it. FOOD SAFETY AND TRANSGENIC ANIMALS At the request of the USDA's Food Safety Inspection Service (FSIS), the Agricultural Biotechnology Research Advisory Committee (ABRAC) working group on transgenic food animals met on April 8 to define scientific issues related to the slaughter of transgenic animals and help in the formulation of regulations for slaughter of transgenic food animals. FSIS enforces the Federal Meat Inspection Act (FMIA) and the Poultry Products Inspection Act (PPIA) to ensure that meat and poultry products for sale are safe, wholesome and accurately labeled. FSIS has been regulating the slaughter of nontransgenic animals derived from biotechnology experiments under experimental animal regulations and has published a criteria document to guide such slaughter (See Bulletin Board Door #1). However, FSIS has not approved any transgenic livestock for slaughter as scientific criteria have not been published for making regulatory decisions about the food safety of transgenic livestock and poultry. The ABRAC Working Group was asked to grapple with such questions as how to define transgenic animals and how transgenic animals should be grouped or classified; i.e. through changes that relate to the animal itself; changes through somatic cell and other cell therapies; and bio-pharm animals. In a preliminary report, the working group generally agreed with the FSIS proposed definition of a transgenic animal as one whose genetic composition has been changed by introducing specific genes (e.g. recombinant DNA) from exogenous sources other than parental germplasm into the line from which the animals are derived (with a suggested clarification that subsequent generations are included). The group proposed an outline of questions making this loop: one for gene products that enhance something that is natural to the species and consideration of secondary effects; one for genes expressing products not normally occurring in the species. Basic elements included: (1) identifying gene product, its concentration and distribution in edible tissues; (2) identifying relevant literature and regulatory history for the product in food; consider secondary influences such as metabolic effects of the gene product and insertional effects. Marker genes, mobile genetic elements and "naked DNA," viral vectors and recombinations, and mosaics were also looked at. Formal, written recommendations of the Working Group will be presented at the full ABRAC meeting on June 30. ABC MEMBERS ENDORSE MERGER WITH IBA At its annual meeting in April, the Association of Biotechnology Companies (ABC) membership endorsed the Association's merger with the Industrial Biotechnology Association (IBA) to form a new organization to be know as the Biotechnology Industry Organization, or BIO. IBA members had previously endorsed the merger which will become formal on July 1, with the submission of documents to the District of Columbia. NEW EUROPEAN BIOTECHNOLOGY FORUM ESTABLISHED While biotechnology industry associations in the United State merge, in Europe a new Forum for European BioIndustry Coordination has been established to strengthen links between bioindustry sectors and provide a more formal network for exchanging news and information. The Forum is made up of federations representing pharmaceuticals, animal health products, food, plant breeders, plants and seeds, diagnostic products, feedstuff additives, pesticides, food and feed enzymes and chemicals. The new European Forum aims to strengthen the power of various sectoral federations in biotechnology issues and to take a common stance on them, while leaving the federations free to state their own views on sector-specific issues. No equivalent group exists in this country. VIVE LA FRANCE In its 2 April edition, SCIENCE reported that nine French laboratories have completed a 3 year, $3 million project to genetically modify grape vines to make them resistant to grape fan-leaf virus (GFLV). GFLV uses nematodes as a vector to enter grape vines and the subsequent malformation and degenerations caused by the virus can lead to serious reductions in yields. Pesticides and costly fallowing of land are the current treatment methods. According to the report, French researchers used Agrobacterium tumefasciens to introduce viral coat protein genes into cells of a hybrid vine variety commonly used as rootstock. With some difficulty, the plants were regenerated from the transformed cells and the researchers are confident that the resulting transgenic vines will remain disease free in upcoming field tests. How French wine drinkers will respond to wines produced from genetically modified grape vines is unknown. The researchers plan to hold a tasting session so experts can judge the quality of wine produced from the plants before widespread planting of transgenic wines is encouraged. Except where noted, the foregoing was compiled by Jay Blowers. The following article was contributed by the National Wildlife Federation, and will appear in the upcoming issue of The Gene Exchange. EIGHT YEARS IN THE MAKING: EPA PUBLISHES BIOTECHNOLOGY RULE In late January, the Environmental Protection Agency announced in the Federal Register its intention to adopt, with modifications, a 1984 interim policy on small-scale field trials of genetically engineered microbial pesticides. For the past eight years under the interim policy, companies have voluntarily notified the Agency when they plan to conduct small-scale tests. Then EPA determines whether additional evaluation and an experimental use permit (EUP) are needed before the test can proceed. This policy is a departure from the usual procedures under the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA). Typically, companies are not required to notify the Agency of pesticide tests conducted on less than ten acres of land or one acre of surface water. Companies must obtain EUPs only where tests exceed these acreages. The Agency altered its policy in the case of genetically engineered microbial pesticides because of the possibility that these novel organisms would pose greater risks than naturally occurring microbial pesticides. Genetic engineering may enhance risk because of its power to create gene combinations heretofore impossible through traditional methods. These new combinations may produce organisms which exhibit novel behavior when released to the environment. PATENT DEVELOPMENTS James R. Cannon - Bell, Seltzer, Park & Gibson, Raleigh, North Carolina A decision handed down by the Court of Appeals for the Federal Circuit on April 20, 1993, IN RE BELL ET AL., discusses the issue of obviousness in regard to patent protection of DNA and peptide sequences. In this case, the claims of the application were directed at nucleic acid sequences encoding human insulin-like growth factors I and II (IGF-I and IGF-II). The relevant prior art references were a pair of publications which disclosed the amino acid sequences for IGF-I and IGF-II and a U.S. patent disclosing a method for isolating a gene encoding a protein for which at least a short amino acid sequence is known; i.e., preparing a DNA probe base corresponding to the amino acid sequence and using that probe to isolate the gene of interest. The patent suggested that the probe be based on amino acids specified by unique codons. The Examiner rejected claims to the nucleic acid sequence as obvious, stating that the ordinarily skilled artisan could determine the DNA sequence when the amino acid sequence is known. The Board of Patent Appeals and Interferences upheld this finding "despite the lack of conventional indicia of obviousness," as "although a protein and its DNA are not structurally similar, they are correspondingly linked by the genetic code." On appeal to the Federal Circuit, the Court reversed the decision of the Board and held that the claims to the DNA sequence were not obvious over these references. The Court reasoned that, although one can use the genetic code to hypothesize possible structures for the corresponding gene, the degeneracy of the genetic code precludes a precise prediction of the gene sequence; in fact, there could be vast numbers of nucleotide sequences that could encode for a specific protein. The Court did caution that this case does not mean that a gene is never rendered obvious even when the sequence of its coded protein is known, and pointed a hypothetical case in which the known amino acid sequence is specified by unique codons as one in which the decision might have been different. This decision is, as has been the custom since the inception of the Federal Circuit, very favorable to patentees. It encourages continuing to sequence a gene even if the sequence of the protein coded for is known, as many such sequences will be, under this decision, held to be nonobvious. In addition, the decision seems to be consistent with earlier decisions of this court on other patent issues. For example, "conception" and "reduction to practice" of a gene in a legal sense do not occur until the actual sequence is known. Also, a prior art reference that does not include the sequence of a gene does not enable the skilled artisan to make the sequence (i.e., the reference is not enabling under sec. 112, first paragraph of the patent statute). The holding of IN RE BELL conforms to the concept that the sequence of a gene is unpredictable despite clues to its identity, such as the amino acid sequence of the encoded protein. On the downside for the patentee, it may ultimately portend a narrower scope of homology will be permissible for patentees claiming a gene sequence and its homologous variants. RESEARCH UPDATE - MICROBES AND PLANTS Charles Hagedorn, Ph.D., Virginia Polytechnic Institute BACULOVIRUS EXPRESSION SYSTEMS The term baculovirus describes a group of rod-shaped DNA viruses that infect insects. The virus particles contain a double- stranded, circular genome that can range in size from 80-150kb. The fact that baculoviruses infect only insect cells makes them safer to use than the adenoviruses or retroviruses traditionally used in mammalian cell culture. Although the baculovirus will fuse with mammalian cells, it cannot replicate, and therefore poses no risk to human handlers. Furthermore, the insect cell lines that serve as hosts to the viruses do not support mammalian pathogens. These aspects of baculovirus expression systems allows work to be performed in a laminar-flow hood, minimizing the need for containment procedures, biohazard considerations, and OSHA regulations. Although insect cells can grow at room temperature, they are still grown in incubators or in warm rooms at 27 degrees C because temperature fluctuations can adversely affect protein expression. The cells do not require carbon dioxide, and they grow rapidly in monolayer or suspension cultures (Glaser, V. Genetic Engineering News, March 1993:10-11). The baculovirus most commonly used to express foreign genes is Autographa californica nuclear polyhedrosis virus (AcMNPV), originally isolated from the alfalfa looper caterpillar. AcMNPV is so named because during its reproductive cycle it produces both extracellular viral particles and occluded viral particles. The latter exist as polyhedral occlusion bodies in the host cell nucleus, in which multiple viral progeny are encased in a polyhedrin protein matrix. This protective fortress enables the virus particles to survive the death and disintegration of the infected insect as well as destructive environmental agents. On ingestion by another caterpillar, the polyhedra dissolve in the gut, releasing virus particles and repeating the lifecycle of infection and replication (Granados R. R., and B. A. Federici (eds.) The biology of baculoviruses, Vols. 1&2, CRC Press, Boca Raton, FL). In the laboratory, AcMNPV is typically grown in cell cultures of Spodoptera frugiperda (the fall armyworm). In cell culture, the 29kd polyhedrin protein is amply produced under the control of a strong promoter. The polyhedrin gene, as well as other genes used in making the occluded form of the virus, such as the p10 gene, are not needed for infection and replication of AcMNPV in cultured cells. This allows for the insertion of a foreign gene in place of the polyhedrin gene, yielding a viral genome that contains the target gene in place of the polyhedrin coding sequence (Knight, P. 1991 ASM News, 57:567-570). Baculovirus expression systems are not new to the research laboratory, and are commonly used to produce reagents for structure/activity screening reactions and to make proteins for use in diagnostic assays. Baculovirus vectors broke through a major regulatory barrier in 1987 with the first FDA approval for testing of a baculovirus-produced product--Vaxsyn, a gp160 HIV vaccine made by MicroGeneSys (Meriden, CT). Improvements in the viral DNA and transfection procedure have made these expression systems more "user-friendly," by dramatically increasing the percentage of recombinants from 1-2% to 75-95%, and reducing the total time for production of recombinant virus from 4 to 6 weeks to 7-10 days. Although the most common systems for cloning foreign genes and expressing recombinant proteins employ E. coli, mammalian cells or yeast, the biotechnology industry is showing a growing interest in commercial applications of baculovirus vectors for protein expression in insect cells. While the main advantage of E. coli, is the relative ease of making a recombinant vector and the high yield of protein (in grams/liter quantities) from these prokaryotic expression systems, E. coli's primary disadvantage lies in its limitations in producing eukaryotic proteins. Many proteins do not fold correctly, and E. coli lacks the enzymes to perform the post- translational modifications that are required for biological activity of many eukaryotic proteins. Mammalian expression systems offer a high level of post-translational processing, but many provide much lower yields of protein (micrograms per liter to 300-400 milligrams per liter) than are possible with E. coli or yeast (Glaser, V. op. cit.). In many ways, baculovirus systems offer the advantages of both E. coli and mammalian cell culture, including reasonable yields (1- 500 mg/L), and sufficient post-translational modification to produce recombinant proteins that are antigenically, immunogenically and functionally similar to the original protein. A large variety of viral, fungal, bacterial, plant and animal genes have been cloned in insect cells using baculovirus expression vectors. The insect cells contain the post- translational modification enzymes necessary to perform glycosylation, fatty acid acetylation, alpha amidation, N- terminal acetylation, phosphorylation, cleavage of signal sequences, and some intron splicing. With respect to glycosylation, baculovirus was once thought to be incapable of this function, but experience has now shown that, if proteins are not harvested until late in the infection process, such enzymatic processing is achieved. Expression of two or more proteins from a single vector, or coinfection with multiple viral vectors enables the synthesis of dimers, heterodimers, and oligomeric complexes. The recombinant proteins produced are soluble and have undergone proper folding and disulfide bridge formation (McCutchen, B. F.,et al., 1991. Bio/Technology, 9:848- 852). Several improvements are needed before insect cell systems can compete on a large scale with E. Coli, mammalian cell, and yeast systems in the commercial arena. These include improved expression vectors that contain new cloning sites or provide higher recombinant frequency with fast and easy identification and purification of recombinant virus, stable insect cell lines, lower-cost materials, more experience with growing large quantities of insect cells in bioreactors, and greater familiarity with the regulatory issues inherent in scaling up to commercial production. New insect lines may offer improved growth properties or contain different modification enzymes that offer specific advantages in post translational processing. There is also a need for lower-cost culture media specifically formulated to improve propagation of insect cells on a commercial scale. Experience with growing insect cells on a commercial scale will help in optimizing conditions for growth in the bioreactor downstream processing, and purifying the recombinant proteins. Production of baculovirus-infected insect cells is now performed as a batch process, because the virus kills the cells in the process of infection and replication. Work is underway to perfect transfer vectors that contain a secretion signal sequence short-circuiting the lytic lifecycle of the virus and enabling the recombinant protein to be secreted from the cells, and protein production to continue without reinfection (Glaser, V. op. cit.). PRINTED COPIES OF THE NEWS REPORT If you prefer the News Report in printed form, call Information Systems for Biotechnology at (703) 231-3747. Or, you may go to the Main Menu, leave a (C)omment for the SysOp giving us your address, and we will include you on the mailing list. ************************************************************ The material in this News Report is compiled by Information Systems for Biotechnology at the Virginia Polytechnic Institute and State University. It does not necessarily reflect the views of the U.S. Department of Agriculture. ****************************END*****************************