Immunology Basics - Immunological Computation: Theory and Applications - page 3

bone marrow-derived stem cells divide into either mature immune cells (to perform
immunological function) or precursors of cells that migrate out of the bone marrow
to continue their maturation process elsewhere (thymus or germinal center (GC)).
In addition to red blood cells and platelets, the bone marrow produces B cells,
natural killer cells, granulocytes, and immature thymocytes.

1.1.1.2 Thymus

In simple terms, the function of the thymus is to produce mature T cells. Some
immature immune cells (thymocytes), also known as prothymocytes, leave the
bone marrow and migrate into the thymus. h rough a maturation process, some-
times referred to as “thymic education,” T cells that are benefi cial to the immune
system are kept, whereas those T cells that might cause a detrimental autoimmune
response are eliminated; mature T cells are then released into the bloodstream for
performing immunological functions.

1.1.1.3 Spleen

h e spleen is an organ, which is made up of B cells, T cells, macrophages, dendritic
cells, natural killer cells, and red blood cells. In addition to capturing foreign sub-
stances (pathogens) from the blood that passes through the spleen, migratory mac-
rophages and dendritic cells bring antigens to the spleen through the bloodstream.
An immune response is initiated when macrophages or dendritic cells present the
antigen to the appropriate B or T cells. h is organ can be thought of as an immu-
nological “conference center.” In the spleen, B cells become activated and produce
large amounts of antibodies in one of its factories, called the general center. Addi-
tionally, old red blood cells are destroyed in the spleen.

1.1.1.4 Lymph Node

h e function of lymph nodes is to act as an immunologic fi lter for the fl uid known as
lymph. Lymph nodes are found throughout the body and they are mostly composed
of T cells, B cells, dendritic cells, and macrophages. Such nodes drain fl uid from most
of the body tissues. Antigens are fi ltered out of the lymph (a fl uid that contains white
blood cells) in the lymph nodes before returning the lymph to circulation throughout
the lymphatic system. Similar to the spleen, macrophages and dendritic cells that
capture antigens present these to T and B cells, thus initiating an immune response.

1.1.2 Immune Cells and Molecules

h e immune system is composed of a variety of cells and molecules, which interact
among themselves to achieve appropriate immunological responses (biological defense).