Chapter 22. Vaccine Synthesis by Recombinant DNA Technology

Abstract

Publisher Summary This chapter discusses the introduction and expansion of new techniques of recombinant DNA or “gene splicing” combined with a resurgence of work on adjuvants. This area has received a great deal of interest from both researchers and commercial enterprises. Work on prevention of infectious diseases continues to be a thriving area of research using the traditional technologies. Vaccination with a live-attenuated vaccine gives a mild or unapparent infection that leads to the induction of virus neutralizing antibodies. These antibodies protect the vaccinated individual from a subsequent infection with the normal pathogen. The protection is generally long lasting and quite effective for many human diseases, such as polio, mumps, measles, rubella, yellow fever. Recently, subunit vaccines or “split virus” vaccines have been investigated that contain only parts of the virus. The most important immunogenic proteins from the virus, the viral surface proteins, are included in these preparations. Many other veterinary vaccines, such as those for Marek's disease, infectious bovine rhinotracheitis, transmissible gastroenteritis, etc., are in common use. The approach that has received the most effort has been the production in the bacterial systems of immunogenic proteins that can induce protective antibodies when incorporated into vaccines. The total nucleic acid sequence of the cloned gene is determined by DNA sequencing methods, and thus by deduction of the amino acid sequence of the surface protein is determined. The gene of interest is then recovered from the E. coli plasmids using restriction endonucleases and reintroduced into other plasmids called expression vectors. An innovative use of recombinant DNA methods has been the creation of novel attenuated viruses or bacteria by the specific removal of genes or gene sequences that cause the virus to be pathogenic. The only example of this has been recently reported concerning the Herpes simplex virus. Advantages to the vaccines derived from recombinant DNA technology are potential for higher safety margin, less expensive products because of high but less costly stablity and quality control process, producing vaccines for diseases not amenable to current technology, possibility of product formulation but not possible with the currently available materials, and possibility to develop the proprietary vaccine products.