CD45R

CD45R contains an extracellular domain, a single transmembrane segment and two tandem intracytoplasmic catalytic domains. It is specifically expressed in hematopoietic cells and has been shown to be an essential regulator of T and B-cell antigen-receptor signaling. It functions through either direct interaction with components of the antigen receptor complexes, or by activating various Src family kinases required for the antigen-receptor signaling. CD45R also suppresses JAK kinases, and thus functions as a regulator of cytokinereceptor signaling.

CD45R represents a restricted form of the CD45 family, which primarily recognizes only cells of B lineage from proB-cell through mature B lymphocytes and, prior to the availability of anti-CD19 MAbs, was commonly used as a pan B-cell marker. It also reacts with certain activated T-cells, as well as non-MHC restricted lytically active lymphokine-activated killer (LAK) cells. MB1 antibody stains preferentially B-cells and their neoplasms but is less specific, as it will also react with some T-cell Lymphomas and Non-lymphoid Tumors. The antigen for this antibody is in the membrane of all B-cells with the exception of plasma cells and some mature T-cells.

CD45R 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. Lauritzen AF, et al. APMIS. 1991;Jul; 99(7):631-9
2. Sott CS, et al. Clin Exp Immunol. 1991;Dec; 86(3):500-5
3. Master PS, et al. Int J Hematol. 1992;Jun; 55(3):235-42
4. Shin SS, et al. Hum Pathol. 1992;Jun; 23(6):686-94

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.