IMMUNE-RESPONSES AND PROTECTIVE EFFECT IN MICE VACCINATED ORALLY WITHSURFACE SPOROZOITE PROTEIN OF EIMERIA-FALCIFORMIS IN ISCOMS

Immunostimulating complexes (ISCOMs) were built after treatment of a p urified surface protein from Eimeria falciformis sporozoites with a pa lmitic acid derivation, leaning to a high ratio (33-64%) of P27 incorp oration in these cage-like structures. P27 kept ifs antigenicity after incorporation in ISCOMs, which induced, after iterative intubations b y the oral route to groups of mice, a systemic IgG response, a local I gA response, and a local enhanced cellular response as demonstrated by lymphoproliferation of mesenteric lymph node cells upon in vitro stim ulation with antigen. This immunization (120 mu g in six oral doses at a-day intervals) afforded mice a partial protection (60%) against a s ubsequent 400 oocyst challenge. The reduction in daily oocyst excretio n was corroborated by significantly different weight losses between im munized and control mice on days 9 and 10 postinfection and the subseq uent death of these control mice. These observations provide the first application of ISCOMs to parasitic intestinal diseases.