Clusters of differentiation classification by Immunophenotyping

Immunophenotyping is the analysis of heterogeneous populations of cells for the purpose of identifying the presence and proportions of the various populations of interest. Antibodies are used to identify cells by detecting specific antigens expressed by these cells, which are known as markers. These markers are usually functional membrane proteins involved in cell communication, adhesion, or metabolism.

Clusters of Differentiation (CD) antigens are widely used for immunophenotyping. CD antigensare a series of surface proteins on leukocytes that serve to differentiate the many types of white blood cells. CD proteins serve as receptors and ligands such as CD4 and CD8 on T lymphocytes which serve to regulate the adaptive immune response. Some CD proteins regulate cell signaling, while others ensure cell adhesion which is an important aspect of adaptive immunity.

This is very confusing and is one reason why hematopathologists keep lots of aspirin in their desks. Nonetheless, if you study lymphomas, you will have to know at least the basics of this scheme. Here are the basics:

All lymphoid cells are reactive for CD45.
Almost all of B-cells are reactive for CD19CD20 and CD22. Certain low-grade B-cell lymphomas are reactive for two markers otherwise usually found on T-cells: CD5 and CD43. Follicular center cell lymphomas (as well as very different fish, lymphoblastic lymphomas) are frequently CD10(+).
Pan T-cell markers (present on almost all T-cells) include CD2CD3CD5, and CD7. Most T-cells mark with either CD4 (helper cells) or CD8 (suppressor cells or cytotoxic cells).
NK cells are frequently associated with CD16CD56, or CD57.

The extent of use of CD antigen expression (immunophenotyping) for identification of leukemias has been constrained by the technique used, flow cytometry, which commonly specifies only three CD antigens in any one assay.

CD4 immunophenotyping in HIV

CD antigens / Cluster of differentiation
CD antigens
CD antigens reagent products
Non-CD cellular antigens
Clusters of differentiation
what is cluster of differentiation
cluster of differentiation nomenclature
cluster of differentiation as markers
cluster of differentiation function
cluster of differentiation classification by Immunophenotyping+
- cluster of differentiation in stem cells
- cluster of differentiation in granulocyte
- cluster of differentiation in monocyte
- cluster of differentiation in T lymphocyte
- cluster of differentiation in helper T cell
- cluster of differentiation in regulatory T cell
- cluster of differentiation in cytotoxic T cell
- cluster of differentiation in B lymphocyte
- cluster of differentiation in platelet
- cluster of differentiation in NK cell
cluster of differentiation 4 / CD4
cluster of differentiation 8 / CD8
cluster of differentiation 3 / CD3+
- cluster of differentiation 3γ
- cluster of differentiation 3δ
- cluster of differentiation 3ε
clusters of differentiation of the B7 family
clusters of differentiation of FC receptor
human Leukocyte Differentiation Antigen workshop