How is the vaccine made and how does it work?

How is the vaccine made?

The Hepatitis B Recombinant Vaccine is made from a protein covering of the virus called HBsAg, which is synthesized from common baker's yeast (Saccharomyces cerevisiae). A plasmid (a small ring of DNA often found in bacteria) containing the gene for HBsAg is inserted into the yeast, instructing it to produce the protein. Pure HBsAg is obtained by breaking open the yeast cells and separating the protein from other cellular parts via biochemical and biophysical techniques. This purified HBsAG is then mixed with aluminum hydroxide and thimerosal (a preservative). ("Recombivax")

No small task: the Hepatitis B vaccines are produced in large quantities while the environment is kept as clean as possible to prevent contamination

Above: How Recombinant DNA is made using DNA coding for HBsAg and a plasmid from bacteria

How does the vaccine work?

The vaccine contains HBsAg, the protein coating of the hepatitis B virus, causing antibodies to be made when it is injected into body. These antibodies will prevent you from getting infected if you ever come in contact with the virus.

1. The adjuvant, which enhances the effect of the vaccine and provokes a greater immune response, and the HbsAg protein are received by a dendritic cell (immune cells).

2. The antigen (in this case, the HbsAg protein) is in turn recognized by a native T cell, a type of white blood cell that can "remember" a certain antigen.

3. The T cells send a signal to B cells, another type of white blood cells, which then make antibodies using the antigen as a template.

4. When a person comes in contact with the Hepatitis B virus, his or her immune system already recognizes the antigen and will quickly destroy the virus before it can multiply.

The vaccine is given as three shots over eight months. The first and second shots are given a month apart, and the third shot is usually given six months after the second. (Planned Parenthood)

The Hepatitis B Vaccine: The Inner Workings