REGULATION OF HOST-CELL FUNCTION BY GLYCOSYLPHOSPHATIDYLINOSITOLS OF THE PARASITIC PROTOZOA

Antigenic variation, antigenic drift, molecular mimicry, intracellular localization and sequestration in privileged sites are important mech anisms of immune evasion by infectious organisms. Added to this howeve r is the phenomenon by which pathogens deliberately regulate host cell function by the production of glycolipids with agonistic or antagonis tic signal transduction capacity. Such pro-active glycolipids are ofte n pathogenicity factors, but they also serve as immunomodulators and i mmunosuppressants, and these activities may serve as mechanisms of imm une evasion. Here we review glycosylphosphatidylinositols and related structures, a novel class of glycolipid common to eukaryotic parasites and their hosts, which recent studies suggest may play a role in immu ne evasion and immunosuppression by regulating host cell function via the activation or suppression of endogenous host signalling pathways.