CD 2

Accurate (CLBT11, F923A11, MEM65, MT910), Ancell (1E7E8), Becton Dickinson (Leu 5, S5.2), Biodesign, Bioprobe/Tha, Biosources (BH1), Boehringer Mannheim (MT26), Caltag Labs (G11), Coulter (T11, 39C15), Cymbus Bioscience (GJ12), Dako (MT910), Exalpha (T6.3), Immunotech (39C1.5), Novocastra (X1X8), Ortho (OKT2), Pharmingen (RPA2.10), Sanbio (MEM65), Serotec and Zymed (RPA2.10).

Fresh-frozen tissue, fresh air-dried cell preparations.

Human T lymphocytes were initially distinguished from B lymphocytes by their ability to produce spontaneous rosettes with sheep red blood cells, a phenomenon mediated by the CD 2 molecule, a glycosylated transmembrane receptor molecule also referred to as T11 antigen or LFA-3 antigen (leukocyte function associated antigen-3). Three functionally important epitope groups have been defined on the human CD 2 molecule, designated T11, T112 and T113 (CD 2R). T111 is the epitope 1 responsible for E-rosetting and T-cell stimulation through this epitope is mediated by an IL-2-dependent pathway. Stimulation of the T11 and T113 epitopes occurs via an alternative pathway (Meuer et al, 1984; Knowles, 1985).
CD 2 is one of the earliest T-cell lineage-restricted antigens to appear during T-cell differentiation and only rare CD 2+ cells can be found in the bone marrow. It is found in all T lymphocytes and natural killer cells but not in B cells or any other cell population. CD 2 binds to its counter receptor CD-58 (LFA-3), a member of the Ig gene superfamily, which locates on the surface of target cells. CD 2 binding to LFA-3 activates T cells and may also have a role in prothymocyte homing as it is known to mediate thymocyte-thymic epithelium adhesion. Although it is known that CD 2 appears after CD 7 but before CD 1, its temporal relationship with CD 3 is less definite, with some recent evidence suggesting that CD 3 appears in the cytoplasm before CD 2 (Osborn et al, 1995).

CD 2 can be considered a pan-T cell antigen and is therefore useful for the identification of virtually all normal T lymphocytes. It is also very useful in the assessment of lymphoid malignancies as it is expressed in the majority of precursor and postthymic lymphomas and leukemias and is not expressed by B neoplasms (Foon & Todd, 1986). As with other pan-T-cell antigens, CD 2 may be aberrantly deleted in some neoplastic T cell populations, especially peripheral T-cell lymphomas. Rarely, sIg+ B cell neoplasms have been described to form spontaneous E-rosettes but these reactions are not mediated via the CD 2 receptor (Knowles, 1989).

CD 2 antibodies can be used for identification of lymphomas and leukemias of T-cell origin. Currently, the monoclonal antibodies available are reactive only in fresh-frozen tissue and not in fixed paraffin-embedded sections.

•Foon KA, Todd RF 1986. Immunologic classification of leukemia and lymphoma. Blood 68: 1-31.

•Knowles DM 1985. Lymphoid cell markers: their distribution and usefulness in the immunophenotypic analyses of lymphoid neoplasms. American Journal of Surgical Pathology 9 (suppl): 85-108.

•Knowles DM 1989. Immunophenotypic and antigen receptor gene rearrangement analysis in T cell neoplasia. American Journal of Pathology 134: 761-785.

•Meuer SC, Hussey RE, Fabbi M et al 1984. An alternative pathway of T cell activation: a functional role for the 50 kd T11 sheep erythrocyte receptor protein. Cell 36: 897-906.

•Osborn L, Day ES, Miller GT et al 1995. Amino acid residues required for binding of lymphocyte function-associated antigen 3 (CD58) to its counter-receptor CD2. Journal of Experimental Medicine 181: 429-434.

Manual of diagnostic antibodies for immunohistology / Anthony S.-Y. Leong, Kumarasen Cooper, F. Joel W.-M. Leong.