Description: This product consists of two fluorochrome-conjugated monoclonal antibodies to distinguish human peripheral CD5+ T cells and CD19+ B cells. The UCHT2 monoclonal antibody (mouse IgG1, κ, HLDA # III518) reacts with human CD5, a 67 kDa protein expressed by the majority of thymocytes and mature T cells and a subset of B cells. Signaling through the CD5 molecule activates T cells and binding of CD5 to its ligand on B cells, CD72, and plays an important role in T-B interaction and proliferation. The HIB19 monoclonal antibody (mouse IgG1, κ, HLDA # V CD19.11) 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.