Which of the following statements is false regarding polysaccharide and conjugated vaccines?

Which of the following statements is false regarding polysaccharide and conjugated vaccines?

• A. Polysaccharide vaccines use carbohydrates found in the external capsule of the bacteria as antigens.
• B. Conjugated vaccines can be used in children as young as 2 months of age because they stimulate both B cell and T helper cell immune responses.
• C. Conjugated vaccines link a polysaccharide to a protein that stimulates a wider immune response.
• D. The conjugate protein used, such as diphtheria, can also provide adequate protection against itself in addition to the polysaccharide.

Answer: (D)

The statement that is false concerns the assertion that the conjugate protein used in these vaccines, like diphtheria, can provide adequate protection against itself along with the polysaccharide. In reality, while conjugated vaccines effectively enhance the immune response to the polysaccharide by linking it to a protein carrier, the protein itself does not offer protection against disease caused by that protein. For example, a conjugate vaccine might help the immune system recognize and respond to polysaccharides from bacteria like Haemophilus influenzae type b (Hib) or Streptococcus pneumoniae, but the protein component (such as diphtheria toxin) does not immunize against diphtheria itself if it is simply used as a carrier for another antigen. Therefore, the assumption that the protein confers protective immunity against the disease it is associated with is inaccurate. In contrast, the other aspects regarding polysaccharide and conjugated vaccines are accurate. Polysaccharide vaccines do indeed utilize components from the bacterial capsule as antigens, and conjugated vaccines' ability to provoke both B cell and T helper cell responses makes them effective for vaccination in young children. The linking mechanism enhances the immunogenicity of the polysaccharide, making these vaccines

The statement that is false concerns the assertion that the conjugate protein used in these vaccines, like diphtheria, can provide adequate protection against itself along with the polysaccharide. In reality, while conjugated vaccines effectively enhance the immune response to the polysaccharide by linking it to a protein carrier, the protein itself does not offer protection against disease caused by that protein. For example, a conjugate vaccine might help the immune system recognize and respond to polysaccharides from bacteria like Haemophilus influenzae type b (Hib) or Streptococcus pneumoniae, but the protein component (such as diphtheria toxin) does not immunize against diphtheria itself if it is simply used as a carrier for another antigen. Therefore, the assumption that the protein confers protective immunity against the disease it is associated with is inaccurate.

In contrast, the other aspects regarding polysaccharide and conjugated vaccines are accurate. Polysaccharide vaccines do indeed utilize components from the bacterial capsule as antigens, and conjugated vaccines' ability to provoke both B cell and T helper cell responses makes them effective for vaccination in young children. The linking mechanism enhances the immunogenicity of the polysaccharide, making these vaccines