Immunology Basics - Immunological Computation: Theory and Applications - page 4

Cells of the immune system
Stem cell

Lymphoid stem cell Myeloid progenitor

Lymphocytes Granulocytes

T cell
progenitor

Neutrophil

B cell
progenitor

Natural
killer cell

Eosinophil

Basophil

Mast cell

Monocyte

Tc cell

Th cell

Memory
cell

Dendritic cell

Plasma
cell

Macrophage

Figure 1.2 Immune cells that contribute to immune response.

Some of those cells that take part in immune response are shown in a hierarchical
diagram in Figure 1.2. h e most relevant ones are described in some detail in the fol-
lowing sections.

1.1.2.1 Lymphocytes, T Lymphocytes, and B Lymphocytes

White blood cells, also called lymphocytes, are very important constituents of the
immune system. h ese cells are produced in the bone marrow, circulate in the
blood and lymph system, and reside in various lymphoid organs to perform immu-
nological functions. h e primary lymphoid organs provide sites where lymphocytes
mature and become antigenically committed. B and T cells constitute the major
population of lymphocytes.
T cells are specialized cells of the immune system, which are matured in the
thymus. h e thymus produces fi ve subpopulations of T cells as follows:

Delayed hypersensitivity T cells, which are a type of T cells that produce cyto-
kines that direct the cellular-mediated immune response and phagocytosis.

Helper T cells, which help the B cells to perform antigen recognition by
releasing cytokines.

Cytotoxic T cells, which kill infected self-cells and tumor cells. h ey also kill
foreign cells.