What are the main ingredients in vaccines? What are the uses of each? This is the question from the teacher, please!

The basic components of a vaccine include antigen, adjuvant, preservative, stabilizer, inactivator and other active ingredients. Vaccine antigenic components of the immune function, immunogenicity should be maintained for a long time and have good stability, vaccines and their compounds in the use of adverse reactions after the less the better.

1. antigen

Antigen is the most important effective active component of the vaccine, is to determine the specific immunogenicity of the vaccine material. Antigen should be able to effectively stimulate the body's immune response, including humoral immunity or (and) cellular immunity, the production of protective antibodies or sensitized lymphocytes, and finally the production of anti-specific antigen protective immunity. The more immunogenic antigens are various types of proteins, polysaccharides, etc., while the lipids are less so. Some of the less immunogenic antigens can be used to enhance the immune response by combining them with adjuvants.

2. Adjuvant

Adjuvant can enhance the specific immune response of the antigen, enhance the antibody response, enhance the mucosal delivery of the vaccine, enhance the immune contact and enhance the immunogenicity of the antigen. The ideal adjuvant should be non-toxic, safe, and stable under non-refrigerated conditions, in addition to having the exact effect of enhancing the immune response to the antigen. The most commonly used adjuvants in vaccines are aluminum adjuvant and oil adjuvant. Newer adjuvants include bacterial toxins, CpG sequences, liposomes, and cytokines.

3. Biocides and preservatives

Preservatives are used to prevent contamination by foreign microorganisms. Generally, liquid vaccines are added with appropriate preservatives to avoid bacterial reproduction from trace contamination during storage. Most inactivated vaccines use preservatives, such as thimerosal, 2-phenoxyethanol, azoxymethyl, etc..

4. Protectant or stabilizer

In order to ensure that the virus or other microorganisms as antigens survive and maintain immunogenicity, the vaccine is often added to the appropriate stabilizer or protectant, such as the commonly used in lyophilized vaccines, lactose, gelatin, sorbitol and so on.

5. Inactivation agent

In addition to the method of inactivation of viral or bacterial antigens can be used physical methods such as heating, ultraviolet irradiation, etc., but also often use chemical inactivation. Commonly used chemical inactivation reagents are acetone, phenol, formaldehyde, etc., these substances have a certain toxic effect on the human body, so after inactivation of antigens must be removed from the vaccine in a timely manner, and after rigorous testing to ensure the safety of the vaccine.

6. Other