Final answer:
Subunit vaccines are formed by isolating a pathogen's key antigens using genetic engineering. They are considered safer and cost-effective, with recombinant vaccines protecting against multiple pathogen strains.
Step-by-step explanation:
Subunit vaccines are immunizations developed by utilizing specific parts of a pathogen—such as its proteins, rather than the entire pathogen. This specific construction offers several advantages including safety, efficiency, and cost-effectiveness. Advanced biotechnological methods like recombinant DNA (rDNA) technology and gene cloning are central to the development of these vaccines.
Using genetic engineering techniques, a gene encoding an antigenic epitope is inserted into a production organism, such as yeast, which then synthesizes the target antigen. The antigen is then purified and used in vaccine formulation. This approach avoids the inclusion of the pathogen's genome, making the vaccine safer. For instance, the hepatitis B vaccine is generated by expressing the hepatitis B surface protein in yeast and purifying it for vaccination.
Moreover, to combat multiple strains of a pathogen, genetic engineering may be employed to create recombinant vaccines. Such vaccines incorporate antigenic components from different strains into one vector, stimulating a comprehensive immune response that guards against various strains of the pathogen.