CD45

The CD45 antigen is a protein which was originally called Leukocyte Common Antigen. It is a Type I transmembrane protein which is in various forms present on all differentiated hematopoietic cells except erythrocytes and assists in the activation of those cells (a form of co-stimulation). It is expressed in Lymphomas, B-cell Chronic Lymphocytic Leukemia, Hairy Cell Leukemia, and Acute Non-lymphocytic Leukemia.

CD45 is a monoclonal antibody that is routinely used to aid in the differential diagnosis of undifferentiated neoplasms, whenever malignant Lymphoma is suspected by the morphological or clinical data. It is a highly specific antibody; thus, a positive result is highly indicative of lymphoid or myeloid origin. Certain types of lymphoid neoplasms may lack CD45 (Hodgkin’s Disease, some T-cell Lymphomas and some Leukemias) so its absence does not rule out a hematolymphoid tumor. This antibody is exclusively expressed by cells of hematopoietic lineage and is present in most benign and malignant lymphocytes, erythrocytes and plasma cell precursors.

CD45 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.

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2. Hall PA, Histopathology. 1988;13:149-160
3. Kurtin PJ, Hum Path. 1985;16:353-365

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.