Conjugate Vaccines

Conjugate Vaccines

History of Conjugate Vaccines

Conjugate Vaccines: In 1987, the very first glycoconjugate vaccine for human use, a Haemophilus influenzae b (Hib) conjugate, was approved in the United States, and it was quickly added to the US baby vaccination schedule. The effectiveness of Hib conjugate vaccines in preventing invasive Hib illness in children [1–3] has sped up with the development of conjugate vaccinations to prevent disease by the other encapsulated bacteria. The necessity for a vaccine formulation that makes bacteria and viruses capsular polysaccharides immunogenic to people most at risk of illness has driven the development of such vaccines.

Pathogens including Neisseria meningitidis serogroup C, Streptococcus pneumoniae, and Hib are all common causes of childhood meningitis and other infection syndromes, and they all have polysaccharide capsules (albeit of different structure) that act as virulence determinants as well as targets for protective antibodies. The relevance of these infections in the young can be explained in part by the low immunogenicity of certain polysaccharides in this age range, as well as the infants’ and children’s incapacity to produce protective antibody responses. Vaccines that only include Hib and pneumococcal capsular polysaccharides have so failed to prevent this high-risk population from illness consistently.

In the prevention of death and disease caused by bacterial infections, conjugate vaccines have proven to be exceedingly effective. The technology is quick, inexpensive, and extremely effective. Intravacc has to have a 20-year track history in conjugate vaccine discovery, development, and testing.

How Do Conjugate Vaccinations Work?

A conjugate vaccination is made by covalently binding a bacterial polysaccharide and peptide to a protein carrier antigen that cannot generate immunological memory on its own. This leads to a more powerful and long-lasting immune response. Intravacc has used a variety of carriers to generate effective conjugate vaccines. Toxoid toxoid, diphtheria toxoid (CRM197), and outer membrane vesicles are among them (OMVs).

Intravacc has perfected the separation of polysaccharides as well as their length. We also have many conjugation processes in place that could be employed with synthesised sugar antigens. Intravacc offers the knowledge and experience necessary to completely characterise combination vaccines.

The Conjugate Platform Developed By Intravacc

Intravac has unique skills and services for evaluating all steps of the vaccine production process and determining vaccine quality. These consist of

  • R&D And Gmp Seed Lots With Clearly Defined Seed Lots
  • Usp And Dsp Are Two Different Types Of Patents.
  • Polysaccharide Purification Methods
  • Method Of Conjugation
  • HPLC
  • Spectroscopy (Mass Spectrometry)
  • NMR
  • Assays Using Colorimetry

We’re also looking into conjugating polysaccharides & peptides to outer sheath vesicles & synthetic polymers, as we’re always looking for new ideas.

Conjugate Vaccines: Our Experience With Combination Vaccinations

The Hib vaccine from Intravacc, which is founded on the conjugated framework, has been on the market in India for many years and has saved countless lives. Intravacc possesses one parent family and has published six articles on its Hib vaccine. Intravacc was recently part of a consortium working on a semi-synthetic conjugate vaccine for Shigella flexneri 2a. Intravacc was in charge of developing and scaling up the technique, as well as producing the vaccine in phase I & II clinical trials. Phase II clinical trials are presently underway for this vaccine.

What Is The Difference Between Polysaccharide And Conjugate Vaccines?

Only the sugar component of the bacterium, the capsule, is used as the antigen in the polysaccharides vaccine to elicit the immune response. Assistant Professor Kristine Macartney explains, “In the conjugate vaccination, it’s actually the sugar attached to the carrier protein.”


Conjugate Vaccines: Despite all of the research into conjugate vaccines, the exact nature of the molecular mechanisms that allow polysaccharide conjugated to protein carriers to also be produced as T-dependent antigens is unknown, and more research is needed. Despite our lack of understanding of mechanisms, the vaccines’ field success is excellent, and licensing of N. meningitidis serogroup C & multivalent S. pneumoniae conjugated vaccines are forthcoming.

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