IMMUNOPATHOLOGY OF HUMAN SCHISTOSOMIASIS MANSONI. II. NK ACTIVITY AND STIMULATION BY SPECIFIC ANTIGEN

Abstract

Sixteen S. mansoni infected and untreated patients (5 with recent infection and 11 with chronic disease) were evaluated for their in v i t r o natural killer ( N K ) activity against the N K sensitive target K562 cell line. N K levels in 9 out of 11 patients (82%) w i th chronic disease were significantly lower (mean = 15 ± 6%), compared with patients recently infected (mean = 41 ± 9% p < 0.001) and with the control group (mean = 38 ± 13% p < 0.001). However, both patients and controls N K activity was stimulated by soluble adult worm antigens (SAWA) , indicating that N K function even in the chronic stage of the infection is able to respond to the parasite antigens. Thes e results suggest the possibility of N K cell participati on as effector mechanism against S . mansoni.