Invitrogen™ CD19 Monoclonal Antibody (HIB19), eBioscience™, Invitrogen™

Description

Description: The HIB19 monoclonal antibody reacts with human CD19, a 95 kDa transmembrane glycoprotein. CD19 is expressed by B cells during all stages of development excluding the terminally differentiated plasma cells. Follicular dendritic cells also express CD19. Together CD21, CD81, Leu13, MHC class II, and CD19 form a multimolecular complex that associates with BCR. Signaling through CD19 induces tyrosine phosphorylation, calcium flux and proliferation of B cells. The SJ25C1 antibody and the HIB19 monoclonal antibody recognize overlapping epitopes. Applications Reported: The HIB19 antibody has been reported for use in flow cytometric analysis, and immunohistochemical staining of frozen tissue sections. It has also been reported in in vitro functional studies. (Please use Functional Grade Purified HIB19, cat. 16-0199, in functional assays. Fluorochrome-conjugated HIB19 is recommended for use in flow cytometry.). Applications Tested: This HIB19 antibody has been tested by flow cytometric analysis of normal human peripheral blood cells. This can be used at less than or equal to 1 μg per test. A test is defined as the amount (μg) of antibody that will stain a cell sample in a final volume of 100 μL. Cell number should be determined empirically but can range from 10^5 to 10^8 cells/test. It is recommended that the antibody be carefully titrated for optimal performance in the assay of interest.

CD19 is a member of the immunoglobulin superfamily, characterized by two Ig-like domains, and is expressed on B cells throughout all stages of development, excluding terminally differentiated plasma cells. It is also expressed on follicular dendritic cells and has been observed on myeloid leukemia cells, particularly those of monocytic lineage. CD19 is considered the earliest and broadest B cell-restricted antigen, and its expression is found in all B cell precursor leukemias. CD19 forms a multimolecular complex with CD21, CD81, Leu13, MHC class II, and the B cell receptor (BCR), playing a crucial role in B cell signaling. As a signal-amplifying coreceptor for the BCR, CD19 lowers the threshold for antigen receptor-dependent stimulation, allowing B cells to respond specifically and sensitively to various antigens through low-affinity antigen receptors. Signaling through CD19 induces tyrosine phosphorylation, calcium flux, and proliferation of B cells. Beyond its role as a BCR coreceptor, CD19 can also signal independently of BCR co-ligation, serving as a central regulatory component upon which multiple signaling pathways converge. This makes CD19 an important functional regulator of both normal and malignant B cell proliferation. Mutations in the CD19 gene can result in hypogammaglobulinemia, a condition characterized by low levels of immunoglobulins, while CD19 overexpression can lead to B cell hyperactivity. CD19 is expressed on 100% of peripheral B cells, as defined by the expression of kappa or lambda light chains, underscoring its significance in B cell function and immune regulation.