LOW-MOLECULAR-WEIGHT PROTEIN LIGANDS FROM ONCHOCERCA VOLVULUSPREFERENTIALLY STIMULATE THE HUMAN GAMMA-DELTA T-CELL V-DELTA-1(+) SUBSET

Onchocerciasis is a chronic infectious disease caused by the filarial nematode Onchocerca volvulus. A minor population of human gamma delta T cells expressing V delta 1 chains is preferentially stimulated by O. volvulus ligands in vitro. Therefore, the nature of the parasite liga nd and the effector functions of V delta 1(+) T cells stimulated by O. volvulus was investigated. A 5- to 30-kDa ligand from the adult paras ite lysate that is sensitive to proteinase treatment was identified, P resentation for preferential stimulation of V delta 1(+) T cells requi red processing, After in vitro stimulation with O. volvulus in the pre sence of interleukin-2, V delta 1(+) T cells produced interferon-gamma but not interleukin-4 and exhibited NK cytolytic activities. It is co ncluded that somatic 5- to 30-kDa protein ligands from O. volvulus sti mulate V delta 1(+) T cells and that V delta 1(+) T cells play a role in immunity to O. volvulus.