What are Vaccines?

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May, 2020

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How Do Vaccines Work?

A vaccine works because it triggers an immune response within the body to a weakened pathogen and that response then remains in the memory of the immune system so that the next time the body is exposed, it knows just what to do.

What is most important to note is the cascade of activities that occur when the immune response is triggered within the body:

An immediate defense of the cells being attacked
An offense that attacks the invading bacteria or virus
A record identifying the specific features of the invading bacteria or virus (antigen) is kept in memory within the immune system

It is in this last functionality of the immune response that is the value of how vaccines operate. By exposing the immune system to a non-lethal or low-dose version of the bacteria or virus, the immune system can overtake the invading bacteria and virus and remember for the future what it needs to do to stop the attack faster and more efficiently.

While there are several cell types that exist within the immune system, the three most common cell types include T cells, B cells and NK cells:

T-Cells

T cell types include the CD4+ T Cells (“helper T cells”) and CD8+ T Cells (“cytotoxic T cells”). Helper T cells play several roles – they assist in the activation of T cells and the maturation of B cells into plasma and memory cells. Cytotoxic T cells destroy virus-infected cells and are implicated in transplant rejection.

B-Cells

B cell types include Memory B cells and Plasma Cells. Memory B cells remain dormant until triggered in the immune response, in which case they provide a stronger and more rapid response. Plasma cells are white blood cells that secrete large volumes of antibodies that bind to the invading bacteria or virus and initiate its neutralization or destruction.

NK or Natural Killer Cells

NK cells (Natural Killer cells) act as clean-up duty in attacking the infected cells of the body rather than the attacking cells.

By: Kiran Chin