DTT
Abbreviation for "Dithiothreitol." DTT is a "thiol reagent" that is useful to us because it can dissolve bonds between cysteine amino acids called "disulfide bonds." DTT is used primarily in reference lab settings as a way to distinguish IgM from IgG antibodies. IgM is a pentamer of five antibody structures held together by disulfide bonds, while IgG is a monomer. If IgM antibodies are exposed to DTT, the disulfide bonds are dissolved and the IgM loses its ability to react and agglutinate RBCs. On the other hand, IgG antibodies are generally unaffected by DTT. Incidentally, DTT may also be used to treat red blood cells to eliminate Kell system antigen activity (the Kell antigens exist on a complex, "cloud-like" structure held together by, you guessed it, disulfide bonds; see the "Kell Kills" podcast for more details). Some other blood group antigens are also altered by DTT (Lutheran, Yta, Dombrock, to name a few), but Kell workups are the most common scenario for antigen modification by DTT. Other, less commonly used examples of thiol reagents are 2-mercaptoethanol (2-ME) and 2-aminoethylisothiouronium bromide (AET).
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