The LC4 monoclonal antibody specifically recognizes the human variable beta 5.1 (Vβ5.1) domain of the beta subunit for the αβ T cell receptor for antigen (TCR αβ). TCR Vβ5.1 is encoded by TRBV5-1 (T cell receptor beta variable 5-1), one of five functional genes within the TRBV5 subgroup in the T cell receptor beta (TRB) locus. The heterodimeric TCR αβ is composed of two disulfide-linked transmembrane glycoproteins, ie, highly variable TCRα and TCRβ chains. These chains are each comprised of an extracellular N-terminal variable (V) region domain followed by a constant (C) region domain, a transmembrane region, and a short C-terminal cytoplasmic tail. The TCR Vβ repertoire is known to be extensive due to the many different combinations of TCR gene segments (Vβ, Dβ, and Jβ) as well as junctional region diversity. TCR Vβ5.1 is variably expressed on subsets of TCR αβ-positive thymocytes and peripheral CD4+ or CD8+ T cells. In association with the CD3 complex of signaling proteins, the TCR αβ recognizes peptide-major histocompatibility complexes (pMHC) that are displayed on other cells to mediate cellular responses. The LC4 antibody is useful for analyzing the levels of TCR Vβ5.1 expressed by individual cells as well as the numbers or frequencies of TCR Vβ5.1-positive cells within test samples. The LC4 antibody can be used to help characterize the TCR Vβ repertoires of T cell populations during health as well as in response to vaccination, infectious disease, aging, transplantation, autoimmunity or cancer.
The antibody was conjugated to BD Horizon BB700, which is part of the BD Horizon Brilliant™ Blue family of dyes. It is a polymer-based tandem dye developed exclusively by BD Biosciences. With an excitation max of 485 nm and an emission max of 693 nm, BD Horizon BB700 can be excited by the 488 nm laser and detected in a standard PerCP-Cy™5.5 set (eg, 695/40-nm filter). This dye provides a much brighter alternative to PerCP-Cy5.5 with less cross laser excitation off the 405 nm and 355 nm lasers.