About PD-1
Programmed cell death protein 1 (PDCD1) is an immune-inhibitory receptor expressed in activated T cells; it is involved in the regulation of T-cell functions, including those of effector CD8+ T cells. In addition, this protein can also promote the differentiation of CD4+ T cells into T regulatory cells. PDCD1 is expressed in many types of tumors including melanomas, and has demonstrated to play a role in anti-tumor immunity. Moreover, this protein has been shown to be involved in safeguarding against autoimmunity, however, it can also contribute to the inhibition of effective anti-tumor and anti-microbial immunity. [provided by RefSeq, Aug 2020]

About CF405S
CF®405S from Biotium is a fluorophore with an excitation peak at 404 nm and an emission peak at 431 nm. It is spectrally similar to Alexa Fluor™ 405. It can be use in fluorescence microscopy, specifically its been validated in Structured Illumination (SIM), and flow cytometry. However, in flow cytometry, superior alternatives are Brilliant™ Violet 421, SuperNova v428 and StarBright Violet 440.