Blood Cells - Tissue Functioning and Remodeling in the Circulatory and Ventilatory Systems - page 53

Chapter 3
Blood Cells

Leukocytes, red blood capsules, and platelets constitute the pool of circulating cells
and pseudocells (Table 3.1 ). Red blood capsules, commonly called erythrocytes or
red blood cells, are mainly devoted to blood gas transport, especially oxygen. When
the demand for oxygen changes, appropriate signals are detected and transmitted
so that the supply of oxygen by the cardiorespiratory system varies to match
the demand. Leukocytes, or white blood cells, coordinate the immune response.
Platelets, also named thrombocytes, are cell fragments that participate in blood
coagulation and inflammation.

3.1 Immunophenotyping of Leukocytes

Molecules on the surface of hematopoietic cells act in the development and
functioning of these cells. Leukocytes possess at their cell surface many accessory
molecules that cooperate with antigen-specific receptors. They participate in cell
adhesion between lymphocytes and other cell types or cell signaling. Numerous
accessory molecules belong to the immunoglobulin (IGSF) superfamily.
Cell-surface antigens expressed on hematopoietic and nonhematopoietic cells
include members of the cluster of differentiation (CD1-CD339) class, lymphocyte
antigens (Ly1-Ly81), as well as markers that do not pertain to these molecule class.
Members of the cluster of differentiation class encompass G-protein-coupled,
protein kinase, and cytokine receptors, ligands of the TNF superfamily, plasmalem-
mal carriers, cell adhesion molecules, erythrocytic antigens, etc.
Lineage markers are cell-surface antigens used for immunophenotyping cells of
a particular developmental lineage. Cells that do not express given lineage markers,
or express these markers at very low levels, are lineage marker negative (Lin

− ,i.e.,

in the mouse, CD2 − ,CD3 − ,CD4 − ,CD5 − ,CD8 − , CD161c − ,PTPRc − , Ly76 − ,

Ly6g − ).