Mis à jour : 3 août 2020
Antibodies are substances that recognize and destroy substances that the body has recognized as “foreign”, that is, as being substantially different from the body. This foreign material that produces antibodies are known as “antigens”. If the foreign material is made up of microorganisms that cause disease, these antigens are known as pathogens.
The body produces antibodies against antigens through a remarkable complicated immune system. The first time your body confronts those antigens it takes some time for this system to go through the complete steps to produce antibodies. Those antibodies will “cure” you of the disease, and, remarkably, will produce a memory of those antigens so that the next time you are in contact with them the body already “knows” how to produce the antibodies, and does so quickly.
Vaccine Definition– Vaccine is an ingredient or substance that helps to protect against particular diseases. The vaccine contains an ingredient that similar to the pathogenic organism and it made from a weak or deadly form of germ, its toxin or protein on its surface. This substance detects the living microbes and destroy it and protect your immune system for future infection.
A vaccine is a biological preparation which provides an active acquired immunity to a particular disease. The term vaccine is derived from the Latin meaning, vacca-cow.
In 1796, Edward Jenner discovered and used the cow-pox virus [Variola vaccinia] to inoculate humans for protection against small pox. A vaccine contains causing microorganism or its toxin or one of its surface proteins in small doses. Vaccines are prepared from the microbial agents or their products which are responsible for infectious diseases. Hence for example the Cholera vaccine is prepared from the cholera producing bacterium Vibrio cholerae.
The vaccine stimulates the body’s immune system to recognize the agent as antigens or foreign particles, destroys it and also remembers it. The immune system is primed by the pathogen present in the vaccine. Hence when the same pathogen infects the host our immune system is ready and launches a war to kill the pathogen.
The two classical kinds of vaccines are “live attenuated” and “killed”, and those names describe the compound. The former is made up on the pathogen (that is the antigen) that has been treated in a way that does not destroy the pathogen, but that changes it in ways that keeps it from causing the disease. The latter is made up of the pathogen that has been “killed”, but is still in a form that will cause antibody production. Generally live attenuated vaccines are considered the most effective, but both kinds are used in many kinds of vaccine preparations.
Base on some factors. They look the immune system responds to the germ, who actually need to be vaccinated against germ and the best method for vaccine production.
Scientists make the 4 types of vaccines like
1〉 Live attenuated Vaccines
2〉 Inactive Vaccines
3〉 Subunit, recombinant, Polysaccharide, and conjugate Vaccines
4〉 Toxoid Vaccine
Live attenuated vaccine: Which means introduction of weekend pathogen when given to the body it starts multiplying and trigger immune response for the development of memory cells.
That generates stronger immunity in the form of Humoral immunity and cell mediated immunity, which will further prevent viral multiplication and it eliminates the vaccine virus (or) pathogen from the body.
However this Live attenuated Vaccine is contra-indicated, i.e. which means should never be administrated to an immuno deficient individual like HIV +ve and Cancer.
Where the Vaccine virus can undergoes rapid and un-controlled multiplication which may be accompanied with mutation (or) genetic change to develop disease causing form known as “VIRULENT” _Causing vaccine derived infection. For example : Vaccine derived Polio Virus (VDPV), So this reduces safety margin of Life attenuated Vaccine
Kill (or) Inactive B: It means pathogen (or) Virus cannot be multiplied and this prevents mutation and vaccine derived infection. Thereby increasing safety margin of this vaccine more than live attenuated vaccine.
However the strength of immunity developed is lower than live attenuated vaccine.
Recombinant vaccine: It means vaccine developed by the process of Genetic Engineering (or) Re-combinant DNA Technology. For example: Sub unit vaccine.
Where only the antigen of pathogen is used as vaccine. For example: Influenza vaccine and Hepatitis B Vaccine.
Modern genetics is now producing new ways of creating vaccines that will not rely on either attenuated or killed pathogens, but will emulate the nucleic acid of the pathogen in a way that will build up an effective safe vaccine.
Genomic vaccines also is another type of vaccine take the form of DNA or RNA that encodes desired proteins. On injection, the genes enter cells, which then churn out the selected proteins. ... In the future, investigators could sequence the genomes of the circulating strains and produce a better-matched vaccine in week
The reason that some vaccines must be frequently reformulated is that all pathogens mutate, and in some cases those mutations will change the pathogen in a way that eludes the ability of the antibodies to destroy them, so new vaccines must constantly be reformulated to try to “catch up” with these mutations. But that cannot happen with 100% certainty, which is one reason why, e.g., the flu vaccine is never called 100% effective.