CD7

CD7 is a 40 kDa transmembrane, single-chain glycoprotein, which is a member of the immunoglobulin gene superfamily. It is expressed in the majority of immature and mature T-lymphocytes, and T-cell Leukemia. It is also found in natural killer cells, a small subpopulation of normal B-cells and in malignant B-cells. It plays an essential role in T-cell interactions and also in T-cell/B-cell interaction during early lymphoid development.

CD7 is a consistently-expressed T-cell antigen in Lymphoblastic Lymphomas and Leukemias; therefore, it is a useful marker in the identification of such neoplastic proliferations. CD7 is expressed in the majority of mature peripheral T-cells, the majority of post-thymic T-cells, NK cells, some myeloid cells, T-cell Acute Lymphoblastic Leukemia/Lymphoma, Acute Myelogenous Leukemia and Chronic Myelogenous Leukemia. Interestingly, CD7 is conspicuously absent in adult T-cell Leukemia/Lymphoma and is not expressed in Sezary cells.

CD7 is a mouse monoclonal antibody derived from cell culture supernatant that is concentrated, dialyzed, filter sterilized and diluted in buffer pH 7.5, containing BSA and sodium azide as a preservative.

1. Knapp W, et al. Leukocyte typing IV:341. Oxford Univesrity Press, Oxford. 1989
2. Miwa H, et al. Leuk Lymphoma. 1996;21(3-4):239-244
3. Saxena A, et al. Am J Hematol. 1998;58(4):278-284

1. Cut and mount 3-4 micron formalin-fixed paraffin-embedded tissues on positive charged slides.
2. Air dry for 2 hours at 58° C.
3. Deparaffinize, dehydrate and rehydrate tissues.
4. Subject tissues to heat epitope retrieval using a suitable retrieval solution such as ImmunoDNA Retriever with Citrate (BSB 0020-BSB 0023) or EDTA (BSB 0030-BSB 0033).
5. Any of three heating methods may be used:
   • Electric Pressure Cooker
     Place standoff rack at base of pressure cooker. Add 1-2 inches of distilled water to the pressure cooker and turn heat to high, and incubate for 15 minutes. Open and immediately transfer slides to room temperature.
   • Water Bath Method
     Place tissues/slides in a pre-warmed staining dish or coplin jar containing the ImmunoDNA Retriever with Citrate or EDTA in a water bath set at 95°-99° C. Incubate for 30-60 minutes.
   • Conventional Steamer Method
     Place tissues/slides in a pre-warmed staining dish or coplin jar containing the ImmunoDNA Retriever with Citrate or EDTA in a Steamer, cover and steam for 30-60 minutes.
6. After heat treatment, transfer slides in ImmunoDNA Retriever with Citrate or EDTA to room temperature and let stand for 15-20 minutes.
7. Wash slides with IHC wash buffer or DI water.
8. Continue IHC staining protocol.