Ref: AP10091 – Clone: 2G9 – Host: Mouse – Method: P – Format: Ready to use

SKU: AP10091 Category: Tag:



CD21, also known as CR2, C3d receptor and EBV receptor), is expressed strongly on mature B cells, follicular dendritic cells and weakly on immature thymocytes and T lymphocytes. In B-cell ontogeny, CD21 appears after the pre-B stage, is maintained during peripheral B-cell development and is lost upon terminal differentiation into plasma cells.CD21 expression is also gradually lost after stimulation of B cells in vitro. CD21 functions as receptor for C3d, C3dg and iC3b Complement components, for EBV and for IFN╬▒.CD21 binds to CD23 and associates with CD19, CD81 and Leu13 to form a large signal-transduction complex involved in B cell activation.

Clone: 2G9

Isotype: IgG2a

Immunogen: Recombinant protein encoding the external domain of human CD21.

Staining pattern: Cell membrane.

Positive control: Tissue sample from tonsil.


This antibody is designed for the specific localization of human CD21 using IHC techniques in formalin-fixed, paraffin-embedded tissue sections.

The CD21 antigen is expressed on mature B cells. The antigen is present with a high density in the follicular dendritic cells (CFD) of B areas of lymphoid tissue. The CD 21 B cells stained moderately and strongly CFD cryostat sections of tissue, while the staining of B cells is reduced or nonexistent in paraffin-embedded sections. Immunostaining of the CFD in FFPE sections is as strong as in cryostat sections of tissue. CD21 immunohistological analysis with the CFD non-Hodgkin’s lymphomas in FFPE sections revealed nodular network usually dense and well defined in the CFD in follicular lymphomas (eg Hodgkin centroblastic / centrocytic) and a diffuse network, weak variable size and some types of lymphoma diffuse (eg centrocytic lymphoma). In non-Hodgkin lymphomas of T origin, the CFD are restricted mainly to the peripheral T cell lymphoma angioimmunoblastic type lymphoma and some cases of pleomorphic.

T lymphoblastic lymphomas, T-CLL and mycosis fungoides are not provided with the network of CFD. Only the nodular lymphocyte-predominant type of Hodgkin’s disease has a characteristic network of CFD.