CD19

CD19 is a human protein encoded by the CD19 gene. CD19 is expressed on follicular dendritic cells and B-cells; it is present on B-cells from earliest recognizable B-lineage cells during development to B-cell blasts, but is lost on maturation to plasma cells. In normal lymphoid tissue, CD19 is observed in germinal centers (on both B-cells and follicular dendritic cells), in mantle-zone cells, and in scattered cells in the interfollicular areas, with an overall immunoreactivity pattern similar to that ofCD20 and CD22. However, in contrast to CD20, CD19 is also expressed in pre-B-cells.

CD19 positivity is seen in the vast majority of B-cell neoplasms (B-Lymphoblastic Lymphoma, Small Lymphocytic Lymphoma/CLL, Mantle Cell Lymphoma, Follicular Lymphoma, Burkitt’s Lymphoma, Marginal Zone Lymphoma, Diffuse Large B-cell Lymphoma, T-cell-rich B-cell Lymphoma, Lymphoblastic Lymphoma, Hairy Cell Leukemia), and commonly at a lower intensity than normal B-cell elements. Plasma cell neoplasms are consistently negative, as are T-cell neoplasms. CD19 expression is not seen in Reed-Sternberg cells of classic Hodgkin’s Disease.

CD19 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. Ishikawa H, et al. Leuk. Lymphoma. 2003;43(3):613-616
2. Zhou LJ, et al. Immunogenetics. 1992;35(2):102-111
3. Kimura M, et al. Int J Hematol. 2007;Jan;85(1):41-8
4. Masir N, et al. Histopathology. 2006;Feb;48(3):239-46

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.