The GAME-46 monoclonal antibody specifically binds to CD18. CD18 is the common β2 integrin chain of LFA-1 (CD11a/CD18, αLβ2 integrin), Mac-1 (CD11b/CD18, αMβ2 integrin), and gp150, 95 (CD11c/CD18, αXβ2 integrin). Expression of CD18 is limited to leucocytes, where it is widely distributed in consort with each of the three integrin α chains (CD11a, CD11b, and CD11c). Among splenocytes, NK cells have the highest density of CD18, and T lymphocytes express a higher density than the remaining cells. The β2 integrins are important mediators of leukocyte-endothelium interactions. It has been reported that GAME-46 antibody blocks in vitro adhesion of LFA-1-expressing cells to the ligands ICAM-1, ICAM-2 and ICAM-3 and of Mac-1-expressing cells to ICAM-1, C3bi, and fibrinogen.
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.