A compound of the formula: wherein R.sub.1 is H, alkyl, aryl, or cyclyl; R.sub.2 is pyranose; R.sub.3 is H or alkyl; m is 2, 3, 4, 5, or 6; n is 0, 1, 2, or 3; o is 0, 1, 2, 3, 4; and p is 1, 2, 3, or 4. Also disclosed is use of the compound to inhibit Th1 differentiation, promote Th2 differentiation, and treat certain disorders.