CD3

CD3 is a multi-subunit complex that interacts with the T-cell receptors

With the exception of NCL-CD3-PS1, monoclonal antibodies are effective on fresh-frozen tissue only. Polyclonal antibodies are effective in paraffin-embedded tissue2. They are directly against the epsilon chain of the molecule.

There are also monoclonal antibodies, which require frozen sections. These include Leu4, which recognises CD3ge and CD3de complexes4.

Immunohistochemical expression

A T-cell marker present on thymocytes, resting and activated T lymphocytes. It is not expressed by B lymphocytes, macrophages, myeloid cells or any other cells, except weakly by Purkinje cells in the cerebellum. Formalin-fixed paraffin-embedded tissues require the use of polyclonal antisera.

Diagnostic utility

T-ALL/T-LBL3
non-neoplastic and neoplastic T lymphocytes. CD3 first appears in the cytoplasm of common thymocytes, subsequently transferring to the surface membrane in medullary thymocytes and mature T-cells.
NK cells: staining is cytoplasmic, due to the presence of CD3e, which is not specific for T-cells, and is detected by polyclonal antibodies. NK cells lack surface positivity.

CD3 negativity occurs in some cases of mycosis fungoides, pleomorphic lymphoma and anaplastic large cell lymphoma. Aberrant loss of expression may help to distinguish them from reactive T-cell proliferations1.

See: Comparison of sensitivities and specificities of T and B cell markers

References

1 Bakels, V., van Oostveen, J.W., van der Putte, S.C., Meijer, C.J. and Willemze, R. Immunophenotyping and gene rearrangement analysis provide additional criteria to differentiate between cutaneous T-cell lymphomas and pseudo- T-cell lymphomas. Am J Pathol 1997;150:1941-9.

2 Leong A S-Y, Cooper K and Leong FJ W-M. Manual of diagnostic antibodies for immunohistology. 2nd edition, 2003

3 Campana D, Thompson JS, Amlot P, et al. The cytoplasmic expression of CD3 antigens in normal and malignant cells of the T lymphoid lineage. J Immunol 1987; 138:648-55

4 Kitamura A, Yamashita Y, Hasegawa Y, et al. Primary lymphoma arising in the nasal cavity among Japanese. Histopathology 2005; 47:523-32