SPECIFIC CELLULAR AND HUMORAL IMMUNE-RESPONSES INDUCED BY DIFFERENT ANTIGEN PREPARATIONS OF ECHINOCOCCUS-MULTILOCULARIS METACESTODES IN PATIENTS WITH ALVEOLAR ECHINOCOCCOSIS

A specific proliferation oi the peripheral blood mononuclear cells (PB MC) stimulated by antigens of Echinococcus sp, has been shown in patie nts with cystic os well as alveolar echinococcosis. However, the devel opment oi a major granulomatous reaction around the parasitic larvae i s a characteristic feature oi the local immune response io E. multiloc ularis while humoral immune responses seem to predominate in E. granul osus infection. The aim oi this study was to analyse the specific prol iferation of the PBMC from 36 patients with alveolar echinococcosis, a nd 23 controls, induced by a crude preparation of E. multilocularis (E mcAg) as well os by two E. multilocularis specific antigen preparation s, the Em2 antigen and the protoscolex (ESAg) antigen. The significant correlation observed between the proliferation index either by Em2 an d ES or by Emc suggests that both antigens account for an important pa ri of the lymphocyte proliferative response. The strong effect of thes e species specific antigens on lymphocyte proliferation is confirmed b y the comparison of the results obtained in this study io those obtain ed in a previous study of specific cellular immunity to E. granulosus antigens in patients with cystic echinococcosis. The proliferation ind ices were significantly elevated in all those 7 patients with a proven AE who were sero-negative using the Emc ELISA, as well as in the 12 p atients also seronegative, but using the Em2 ELISA. In 5 seronegative patients who had had a complete resection of the parasitic lesions two years before the lymphocyte proliferation evaluation, the Pi was abov e the threshold value for two dilutions of EmcAg. PI under the thresho ld values were obtained only in patients with residual lesions. These results suggest that E. multilocularis specific antigens promote the p roliferation of lymphocytes which could be TH 1 cells, responsible for the intense periparasitic granulomatous reaction characteristic of al veolar echinococcosis.