Dr. Murai Éva szerk.: Parasitologia Hungarica 22. (Budapest, 1989)

CONCLUDING REMARKS Over a decade of work on the immune response to intestinal helminths a great deal of detailed information has been accumulated. Despite the abundant research concerning the mechanism of protective immunity against intestinal worms, no important conceptual development has taken place since the early eighties. The question of the exact nature of the damage which renders worms vulnerable by the host's expulsion mechanism has commanded much less attention. In principle, immune reaction can affect intestinal helminths either by a target-orientated direct, or an entero-allergic indirect mechanism (Fig. 5). The direct mechanism involves a direct helminthotoxic potential of specific antibodies, sensitized effector cells, mediators or other substances, while in the case of the indirect mechanism the specific factors of the immune response participate in bringing about a local nonspecific inflammatory response, and there is no need of any particular host component to have a direct anti-worm action (KASSAI 1982). Most evidence discussed In the present review is compatible with the indirect mechanism of worm expulsion. Further studies are needed to improve our knowledge on the nature of the interference which develops in intestinal worms affected by the host's immune response. A/ Target-orientated direct mechanism It involves direct toxic action of specific antibodies, sensitized effector cells, cell products /lymphokines/

, humoral factors of non antibody character, combined action of several factors B/ Enteroallergic indirect mechanism It involves local, nonspecific pathologic lesions, inflammatory reaction, alteration of the intestinal milieu, which lead to deprivation of worms from factors vital for their physiology /to be identified/ Fig. 5 Hypothetical mechanisms of worm rejection from the intestine (Kassai, 1982)