Memory T Cells

Question.

207. Memory T cells can be identified by using the following marker:

1. CD45 RA.

2. CD45 RB.

3. CD45RC.

4. CD45RO.

Answer

4. CD45RO.

Reference

Harrison's15^th Edition,Pg-1808 Table 305 -1

Quality

Spotter

Status

New

QTDF

Harrison

Discussion

T lymphocytes require the thymus for their development and show a set of characteristic surface glycoproteins and their own form of receptor, as described above. They can be divided into types: cytotoxic T lymphocytes that carry the CD8 glycoprotein and helper T cells that carry CD4 in mice. The latter can be divided according to the cytokines they release on antigen contact into Th1 (IL-2 and interferon-gamma;) and Th2 (IL-4, -5, and -10).

T cells may also be divided into those in an inactive state (virgin T cells) and preactive state (memory T cells) by the CD45 glycoprotein isotype on the cell surface. Thus, there is a very high proportion of CD45RA positive (virgin) in cord blood, and CD45RO (memory) T cells appear during early life. In vitro, T-cell proliferation to recall antigens (e.g. tetanus toxoid) involves CD45RO T cells, whereas T-cell proliferation to alloantigens involves both CD45RA and -RO populations.

Explanation

1. CD45 RA.
1. Subset T cells,
2. Medullary thymocytes,
3. "Naive" Tcells
2. CD45 RB.
1. All leukocytes
3. CD45RC.
1. Subset T cells,
2. Medullary thymocytes,
3. "naive" T cells
4. CD45RO.
1. Subset T cells,
2. Cortical thymocytes,
3. "Memory" T cells

Comments

A new Question from Harrison !!

Tips

The development of monoclonal antibody technology led to the discovery of a large number of new leukocyte surface molecules. In 1982, the First International Workshop on Leukocyte Differentiation Antigens was held to establish a nomenclature for cell-surface molecules of human leukocytes. From this and subsequent leukocyte differentiation workshops has come the cluster of differentiation (CD) classification of leukocyte antigen