The MH3-2 monoclonal antibody specifically recognizes the human variable beta 5.2 (TCR Vβ5.2) and variable beta 5.3 (TCR Vβ5.3) domains of the beta subunit for the αβ T cell receptor (TCR Vβ5.2/5.3). The TCR Vβ5.2 and TCR Vβ5.3 domains are encoded by the TRBV5-6 (T cell receptor beta variable 5-6; also known as TCRBV5S2) and TRBV5-5 (T cell receptor beta variable 5-5; TCRBV5S3) gene segments of the multimembered Vβ5 subfamily within the TRB (T cell receptor beta locus), respectively. Functional T-cell receptor beta chains (TCR-β) are generated by genomic rearrangement of TCR variable (Vβ), diversity (Dβ), joining (Jβ) and constant (Cβ) region gene segments by precursor T cells. Distinct αβ TCR containing either TCR Vβ5.2 or TCR Vβ5.3 are clonally expressed on subsets of thymocytes or peripheral CD4+ or CD8+ T cells. These TCR β beta chains can heterodimerize with TCR α chains to form αβ TCR that function as signaling T cell receptors for antigen. Human αβ TCR recognize peptides presented by HLA (MHC) molecules and in conjunction with the associated CD3 complex, can transduce intracellular signals that initiate precursor or mature T cell responses. The MH3-2 antibody may be useful for analyzing the frequencies or numbers of TCR Vβ5.2/5.3-positive thymocytes or mature T cells as well as the levels of TCR Vβ5.2/5.3 expressed by these cells. The MH3-2 antibody can be used in research applications such as flow cytometry to help characterize the TCR Vβ repertoires of precursor or mature T cell populations.
The antibody was conjugated to BD Horizon™ BUV563 which is part of the BD Horizon Brilliant™ Ultraviolet family of dyes. This dye is a tandem fluorochrome of BD Horizon BUV395 which has an Ex Max of 348 nm and an acceptor dye. The tandem has an Em Max at 563 nm. BD Horizon BUV563 can be excited by the 355 nm ultraviolet laser. On instruments with a 561 nm Yellow-Green laser, the recommended bandpass filter is 585/15 nm with a 535 nm long pass to minimize laser light leakage. When BD Horizon BUV563 is used with an instrument that does not have a 561 nm laser, a 560/40 nm filter with a 535 nm long pass may be more optimal. Due to the excitation and emission characteristics of the acceptor dye, there may be spillover into the PE and PE-CF594 detectors. However, the spillover can be corrected through compensation as with any other dye combination.