IMMUNOLOGICAL SYSTEM AND SCHISTOSOMA-MANSONI - CO-EVOLUTIONARY RMMUNOBIDOGY - WHAT IS THE EOSINOPHIL ROLE IN PARASITE-HOST RELATIONSHIP

Schistosomes, ancestors and recent species, have pervaded many hosts a nd several phylogenetic levels of immunity, causing an evolutionary pr essure to eosinophil lineage expression and response. Schistosoma mans oni adult worms have capitalized on the apparent adversity of living w ithin the mesenteric veins, using the dispersion of eggs and antigens to other tissues besides intestines to set a systemic activation of se veral haematopoietic lineages, specially eosinophils and monocytes/mac rophages. This activation occurs in bone marrow spleen, liver, lymph n odes, omental and mesenteric milky spots (activation of the old or pri mordial and recent or new lymphomyeloid tissue), increasing and making easy the migration of eosinophils, monocytes and other cells to the i ntestinal periovular granulomas. The exudative perigranulomatous stage of the periovular reaction, which present hystolitic characteristics, is then exploited by the parasites, to release the eggs into the inte stinal lumen. The authors hypothesize here that eosinophils, which hav e a long phylogenic story, could participate in the parasite-host co-e volution, specially with S. mansoni, operating together with monocytes /macrophages, upon parasite transmission.