About HLA DQB1
HLA-DQB1 belongs to the HLA class II beta chain paralogs. This class II molecule is a heterodimer consisting of an alpha (DQA) and a beta chain (DQB), both anchored in the membrane. It plays a central role in the immune system by presenting peptides derived from extracellular proteins. Class II molecules are expressed in antigen presenting cells (APC: B lymphocytes, dendritic cells, macrophages). The beta chain is approximately 26-28 kDa and it contains six exons. Exon 1 encodes the leader peptide, exons 2 and 3 encode the two extracellular domains, exon 4 encodes the transmembrane domain and exon 5 encodes the cytoplasmic tail. Within the DQ molecule both the alpha chain and the beta chain contain the polymorphisms specifying the peptide binding specificities, resulting in up to four different molecules. Typing for these polymorphisms is routinely done for bone marrow transplantation. Alternative splicing results in multiple transcript variants. [provided by RefSeq, Sep 2011]

About FITC
Fluorescein isothiocyanate (FITC) has an excitation peak at 495 nm and an emission peak at 519 nm. The name FITC is a misnomer in that the isothiocyanate is a reactive form of this dye. Once FITC is conjugated to an antibody, it is simply Fluorescein conjugated. FITC is one of the most widely used dyes for fluorescent applications, therefore most instruments come standard with a 488 nm laser and FITC filter set up. FITC is commonly conjugated to secondary antibodies and used in applications such as flow cytometry, immunocytochemistry, and immunohistochemistry. FITC is relatively dim, sensitive to photobleaching and it is susceptible to changes is pH. There are better performing alternatives to FITC, like Vio®Bright 515, Alexa Fluor™ 488, iFluor® 488, CF®488A and DY-488. FITC is a long-time generic dye with no sole manufacturer or trademark.