HOST-PARASITE RELATIONSHIP BETWEEN CONGENITAL TOXOPLASMA INFECTION AND MOUSE-BRAIN - ROLE OF SMALL VESSELS

Small vessels showing inflammatory cell infiltrates were invariably ob served in the vicinity of intact Toxoplasma tissue cysts within the br ains of mice congenitally infected with the protozoan. Lymphocytes wer e observed in intimate contact with the luminal aspect of the endothel ium, penetrating into the thickened basal lamina and in the perivascul ar area, which also contained macrophages and neutrophilic granulocyte s. Rarely, lymphocytes were observed attached to the outer membrane of the host neurone which contained a Toxoplasma tissue cyst and within the inflammatory infiltrate associated with a disintegrating cyst. An hypothesis is presented which combines these morphological observation s to explain the events associated with tissue cyst associated recrude scence of latent Toxoplasma infection in mouse brain.