How is a polysaccharide vaccine made?

Conjugate subunit vaccines (e.g., Haemophilus influenzae type b and pneumococcal conjugate vaccines) are produced by chemically attaching a polysaccharide from the surface of bacteria to a protein molecule through a process called conjugation.

How are conjugate vaccines produced?

A new technology has been developed for the production of conjugate vaccines by an in vivo conjugation process. Instead of chemically conjugating polysaccharides to proteins, the conjugate is directly synthesized in appropriately engineered E. coli cells.

What are polysaccharide conjugate vaccines?

Polysaccharide protein conjugate vaccines are primarily used for the prevention of bacterial infections. Some pathogenic bacteria are covered with a polysaccharide capsule that primarily helps protect the bacteria from phagocytosis, or uptake of the bacteria by immune cells.

What is the main reason for conjugating a polysaccharide vaccine?

Conjugate vaccines have been developed to induce a robust immune response against bacterial capsular polysaccharides (CPSs). CPSs are long polymers composed of many repeating units of simple sugars and serve as a protective external layer for many bacteria.

Are boosters required for polysaccharide vaccines?

Polysaccharide Meningococcal Vaccines They are poorly immunogenic in infants, do not provide a booster response, do not substantially decrease meningococcal pharyngeal colonization and therefore do not provide herd protection, and can induce the phenomenon of immunologic hyporesponsiveness.

What is the difference between conjugate and polysaccharide vaccine?

In the polysaccharide vaccine, only the sugar part of the bacteria, the capsule, is included as the antigen to stimulate the immune response. “In the conjugate vaccine, it’s actually the sugar joined to the carrier protein,” says Associate Professor Kristine Macartney.

What are examples of conjugate vaccines?

Examples include Haemophilus Influenza Conjugate Vaccine (Hib) and Pneumoccocal Conjugate Vaccine (Prevnar®).

What type of vaccine is conjugate?

The most commonly used conjugate vaccine is the Hib conjugate vaccine. Other pathogens that are combined in a conjugate vaccine to increase an immune response are Streptococcus pneumoniae and Neisseria meningitidis”, both of which are conjugated to protein carriers like those used in the Hib conjugate vaccine.

Why do we use conjugate vaccine?

In this case, a conjugate vaccine is used in order to invoke an immune system response against the weak antigen. In a conjugate vaccine, the weak antigen is covalently attached to a strong antigen, thereby eliciting a stronger immunological response to the weak antigen.

What are the advantages of conjugate vaccines?

Further advantages of the conjugate vaccines are their ability to elicit immunological memory and to reduce asymptomatic carriage of the bacteria, resulting in marked herd immunity.

What is the difference between a conjugate and polysaccharide vaccine?

Why are polysaccharide vaccines not effective in children?

Polysaccharide vaccines These vaccines are safe, with mild local adverse events, and have good efficacy (>85%) in older children and adults. However, due to lack of a T-helper response, the vaccines are poorly immunogenic below 2 years of age, fail to induce immunologic memory and provide protection for only 3–5 years.

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