Information Technology Reference
In-Depth Information
MHC Molecule
T cell
1
Receptor
CD8
CD4
MHC Class I
MHC Class II
1
1
1
1
1
1
Fig. 1.
Extract of page 30 of [20] mapped onto a UML class diagram
Another extract is: “
T cells are activated to produce armed effector T cells when
their encounter their specific antigen in the form of a peptide:MHC complex on the
surface of an activated antigen-presenting cell (APC) … The most important APC are
the highly specialized dentritic cells … Macrophages can also be activated to express
co-stimulatory and MHC class II molecules … B cells can also serve as APC in some
circumstances... Dentritic cells, macrophages and B cells are often known as profes-
sional antigen presenting cells
”
MHC
Molecule
Antigen
Antigen Presenting
Cell
MHC class I
MHC class II
CD4
Professional APC
B cell
Dentritic
Macrophage
T cell receptor
CD8
Fig. 2.
Extract of page 319 of [20] mapped onto a UML class diagram
In figure 2, looking attentively, the classes CD4 and CD8 are represented as “asso-
ciation classes” between APC and MHC, since they interact with APC only when
these later express on their surface a MHC molecule. One can see how the second
diagram is aimed at completing and refining the previous one by specifying the prop-
erties of the T cell receptors and how they do interact with the APC. These two class
diagrams still are quite incomplete but need to be taken as simple examples of how
UML symbols allow a more formal and computational language, derivable from the
qualitative language of immunology, in the way to computer simulations.
In many immune system simulations [1, 6, 7, 21] (included the simple one to be
presented in the next section), it is the immune response to pathogens by either T cells
or B cells followed by the memorization of this response which is under investigation.
Almost all simulations consider a succession of B or T cell states: departing from a
