The Specific Immune Response

The specific immune response involves many different types of white blood cells. The role of the white blood cells is to stimulate the correct antibodies to be made. These antibodies will neutralise anything that has the particular antigen the immune system is on the lookout for. This antigen of course is the marker for a pathogen that has evaded the primary immune response and is now infecting the internal parts of the body.

The specific immune response also provides long term protection for the body against the pathogen. The memory cells produced can stay in the body for many years stopping infection if the same pathogen invades the body again.

The white blood cells involved in stimulating the antibody repsonse are

• T lymphocytes - made in the thymus
• T helper cells (Th) - release chemical messengers called cytokines. These cytokines stimulate B cells to develop and stimulate phagocytosis.
• T killer cells (Tk) attack and kill any body cells that have phagocytosed any pathogens and so display the foreign antigen.  
• T memory cells (Tm) Provide long term immunity to the host. 
• T regulator cells (Tr) shut down the immune response after the pathogen has been removed. they are also involved in preventing the immune cells from attacking the hosts body cells in an autoimmune response. 

• B lymphocytes - made in the bone marrow
• Plasma cells make antibodies.
• B memory cells (Bm) which remain in the body as memory cells. 

How cells work together

When cells communicate - send signals to one another, it is called cell signalling. Signals received usually turn on genes or start signalling cascades (chains of messages) inside the cell receiving the message. 

Cell signalling in the immune response

The specific immune response is a highly organised web of cells sending signals to each other. 

CLICK HERE TO SEE A SIMPLE EXAMPLE

Cytokines

There are many different cytokines, released from different cells. The cytokines are specific for the target cell as only the target cells have the specific receptor for the cytokine.

Examples of cytokines.

Here are some examples of cytokines and their actions. The cytokines we are looking at are 

• monokines
• interleukins
• interferon

Macrophages release monokines. Some monokines attract neutrophils to the macrophages. Some monokines cause B cells to differentiate and release antibodies.

T cells and macrophage release interleukins. The cytokine interleukin stimulates proliferation (a rapid rush of cell division by mitosis, over and over again) of B and T cells. This produces thousands of identical B and T cells and is called clonal expansion.  The T and B cells then differentiate

Many cells release interferon. 
Interferon activates T killer cells. It also inhibit virus replication.

Now let's look at this complicated map of immunity in more detail! Take it slowly - it's not so bad.