The 2F1 monoclonal antibody specifically binds to KLRG1 (Killer cell Lectin-like Receptor G1), which is the mouse homolog of the rat mast cell function-associated antigen (MAFA), on all mouse strains tested (eg, AKR/J, BALB/c, C3H/HeN, C3H.SW, C57BL/6, DBA/1, SJL, 129/J). Unlike rat MAFA, which is expressed on mast cells, mouse KLRG1 is expressed on a large subset of NK cells, lymphokine-activated killer (LAK) cells, adherent LAK (A-LAK) cells, subsets of activated CD8+ T lymphocytes, and small fractions of CD4+ and CD8+ T cells, but not mast cells. The expression of KLRG1 is correlated with reduced proliferative capacity of activated T lymphocytes or reduced effector functions of activated NK cells. KLRG1 plays a role in the regulation of leucocytes of both the innate and adaptive immune system. The 2F1 mAb reportedly stains the rat basophilic leukemia cell line, RBL-2H3, which is known to express MAFA. The KLRG1 protein is an inhibitory lectin-like type II transmembrane receptor containing a cytoplasmic motif similar to ITIM (Immunoreceptor Tyrosine-based Inhibitory Motif); its ligand has not been identified KLRG1 is expressed mainly as a homodimeric molecule consisting of two N-glycosylated subunits of approximately 30-38 kDa. The level of KLRG1 expression is reduced in MHC class I-deficient mice, although direct binding of KLRG1 to MHC class I antigens could not be detected. Crosslinking of KLRG1 by 2F1 mAb reduces TCR-mediated Ca++ mobilization and cytotoxic responses (but not IFN-γ production) by CD8+ T cells and inhibits IFN-γ and TNF production and redirected lysis by NK cells.
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.