Final answer:
Subunit vaccines employ various antigens without using whole pathogens and include recombinant, toxoid, and conjugate vaccines. These vaccines are safe, precise, and use elements such as viral proteins or polysaccharides to stimulate immunity.
Step-by-step explanation:
Subunit vaccines are a type of vaccine that present one or more antigens without introducing whole pathogen cells or viruses to the body. These antigens trigger the immune system to produce an immune response, leading to immunity against the disease-causing organism. The three types of subunit vaccines include:
- Recombinant subunit vaccines, which use a piece of a pathogen created by genetic engineering to stimulate an immune response.
- Toxoid vaccines, which use a toxin produced by the pathogen that has been inactivated to stimulate immunity. This type of vaccine is specifically effective against bacteria that produce toxins.
- Conjugate vaccines, which consist of a protein component conjugated to a polysaccharide antigen, enhancing immune response especially in young children.
These vaccines are known for their safety and cost-effectiveness, with modern technology such as recombinant DNA playing a significant role in their development. Subunit vaccines target specific antigens, such as viral proteins or polysaccharides, making them a precise and focused immune system training tool.