The 1F11/TSLPR monoclonal antibody specifically binds to Thymic Stromal Lymphopoietin Receptor (TSLPR). TSLPR is a member of the hematopoietin receptor superfamily and is also known as Cytokine Receptor-like Factor 2 (CRL2, CRLF2Y, CRLF2). The functional TSLPR complex consists of two subunits, TSLPR and the alpha subunit of the Interleukin-7 Receptor (IL-7Rα). Analysis of the TSLPR reveals sequence similarity with the common cytokine receptor gamma chain (γc; CD132). Functional TSLPRs are expressed by epithelial cells and a variety of hematopoietic cell types, including thymocytes, T cells, B cells, natural killer T cells, monocytes, macrophages, basophils, and dendritic cells (DC). Recent studies indicate that TSLP can activate multiple STAT (Signal Transducer and Activator of Transcription) signaling proteins. TSLP enhances the maturation and viability of DC. It strongly induces DC expression of the CD40 and CD80 costimulatory molecules and chemokines, e.g., TARC (Thymus and activation-regulated chemokine; CCL17) that can attract Th2 effector cells. TSLP supports B cell development. TSLP costimulates the proliferation of naïve T cells in the presence of mature DC. TSLP is also able to increase the sensitivity of T cell receptor-activated CD4+ T cells to low doses of IL-2. In the presence of TSLP, the acute myeloid leukemia-derived cell line, MUTZ-3, shows induced growth and reduced apoptosis. CRLF2 deregulated gene expression is thought to be involved in lymphoid transformation in B-cell precursor acute lymphoblastic leukemia. The 1F11/TSLPR antibody is reportedly a neutralizing antibody.
The antibody was conjugated to BD Horizon™ BUV661 which is part of the BD Horizon Brilliant™ Ultraviolet family of dyes. This dye is a tandem fluorochrome of BD Horizon BUV395 with an Ex Max of 348-nm and an acceptor dye with an Em Max at 661-nm. BD Horizon Brilliant BUV661 can be excited by the ultraviolet laser (355 nm) and detected with a 670/25 filter and a 630 nm LP. Due to cross laser excitation of this dye, there may be significant spillover into channels detecting APC-like emissions (eg, 670/25-nm filter).
Due to spectral differences between labeled cells and beads, using BD™ CompBeads can result in incorrect spillover values when used with BD Horizon BUV661 reagents. Therefore, the use of BD CompBeads or BD CompBeads Plus to determine spillover values for these reagents is not recommended. Different BUV661 reagents (eg, CD4 vs. CD45) can have slightly different fluorescence spillover therefore, it may also be necessary to use clone-specific compensation controls when using these reagents.