GAMMA-DELTA T-CELLS - THEIR IMMUNOBIOLOGY AND ROLE IN MALARIA INFECTIONS

The status of research on gamma delta T cells is reviewed. Recent rese arch shows that gamma delta T cells may see antigens in an immunoglobu lin-like manner and that non-peptidic substance can be antigens for th ese cells. Considerable advances have been made in defining the immuno biology of gamma delta T cells, with evidence for sentinel, protective and immunoregulatory roles. Research on gamma delta T cells in malari a infections suggests that gamma delta T cells are mediators of protec tive immunity, most probably through the production of Th1 cytokines s uch as TNF alpha, TNF delta and IFN gamma and that excessive productio n of such cytokines may contribute to pathology. Our data on the featu res of the peripheral blood gamma delta T cell response in humans infe cted with Plasmodium falciparum show that there is considerable variat ion between individuals in the relative expansion of gamma delta T lym phocytes following primary or secondary infection. They confirm that a ctivation of gamma delta T cells occurs during P. falciparum infection and that activated cells can persist for many weeks after treatment. The possibility that gamma delta T cells have an immunoregulatory func tion in malaria infections is proposed. (C) 1997 Australian Society fo r Parasitology. Published by Elsevier Science Ltd.