OCH

α-GalCer, also known as KRN7000, is the prototypical agonist for NKT cells that possesses an 18C phytosphingosine and a 26C acyl chain. Because many analogs of this Ag have been generated that promote distinct NKT cell responses, a critical question is whether the altered functionality is determined by their differential impact on TCR binding. A panel of 10 different AGLs had been investigated: (1) α-GalCer, (2) OCH, with C9 phytosphingosine and C24:0 acyl chains; (3) C20:2, a C20 acyl chain and cis-diunsaturation at C11 and 14; (4) α-GlcCer, identical ceramide component to C20:2, but α-linked glucosyl head group; (5) 3′,4″-deoxy-α-GalCer, both the 3′-OH of the sugar and the 4′-OH of the sphingoid base are removed; (6) 4′,4″-deoxy-α-GalCer, both the 4′-OH of the sugar and the 4′-OH of the sphingoid base are removed; (7) 4′-deoxy-α-GalCer, with a 4′-deoxy-sugar but retaining the 4′-OH group on the sphingoid base; (8) the 4″-deoxy-α-GalCer AGL, with an α-Gal sugar, but lacking the 4′-OH on the sphingoid base; (9) α-GalCer (C24) and (10) α-GlcCer (C24), both with 24C acyl and 18C sphingosine chains.