ANTIGEN-SPECIFIC PROLIFERATION AND INTERFERON-GAMMA AND INTERLEUKIN-5PRODUCTION ARE DOWN-REGULATED DURING SCHISTOSOMA-HAEMATOBIUM INFECTION

Antigen-specific cellular immune responses were examined in persons pr eviously infected with Schistosoma haematobium and who were, 2 years a fter chemotherapy, either free from infection (n = 17) or reinfected ( n = 20), Proliferation to adult worm antigen (AWA) was significantly h igher in uninfected than in reinfected subjects (P = .02), whereas res ponses to soluble egg antigen (SEA) remained low in both groups. Inter leukin (IL)-5 production in uninfected persons in response to AWA and SEA was higher than in infected subjects (P =.05 and P < .001, respect ively), while IL-4 and IL-13 release was similar in the 2 groups. Leve ls of interferon-gamma to AWA and to SEA were inversely correlated wit h egg output (P =.03 and P =.02, respectively). These data indicate th at the presence of schistosome infection leads to T cell proliferative hyporesponsiveness and that both typical Th1 and Th2 cytokines can be down-regulated by active infection.