About IL-21
This gene encodes a member of the common-gamma chain family of cytokines with immunoregulatory activity. The encoded protein plays a role in both the innate and adaptive immune responses by inducing the differentiation, proliferation and activity of multiple target cells including macrophages, natural killer cells, B cells and cytotoxic T cells. Dysregulation of this gene plays a role in multiple immune-mediated diseases including lupus, psoriasis and chronic inflammatory diseases. Alternatively spliced transcript variants encoding multiple isoforms have been observed for this gene. [provided by RefSeq, Dec 2011]

About Brilliant Violet 421
Brilliant™ Violet 421 (BV421) is a Violet-emitting non-tandem polymer fluorophore that can be excited by the 405 nm Violet laser and collected using a 450/50 bandpass filter. BV421 has an excitation peak at 405 nm and an emission peak at 421 nm, and is spectrally similar to Alexa Fluor™ 405 and Cascade Blue. Other dyes that are considered similar include SuperNova V428 (Beckman Coulter), StarBright Violet 440 (Bio-Rad) and SuperBright 436 (Thermo Fisher). BV421 is very bright and is most commonly used for flow cytometry. Its photostablity, fixation stablity, and non-toxicity properties also make BV421 useful for cell sorting and live cell Fluorescence Microscopy applications. This dye is part of the Brilliant™ Violet dye line of fluorescent polymers. Brilliant™ Violet 421 polymer is employed as the donor molecule in a series of tandem dyes with acceptor molecules emitting at various points across the visible light spectrum. The Brilliant™ Violet dyes are a superior alternative to QDot nanocrystals and similar to SuperNova dye from Beckman Coulter and StarBright dyes from Bio-Rad.