Effect of a Purified Excreted Factor from Leishmania brasiliensis on Macrophage Activity

Abstract
The effect of a purified glycoprotein excreted to the culture medium by Leishmania brasiliensis on the endocytic and degradative capacity of macrophages was studied. It was demonstrated that 125I-albumin incorporation as well as its intracellular fate by mouse peritoneal or tumor J774-G8 macrophages was greatly reduced when they were treated with excreted factor (EF). EF appears to alter also membrane properties in addition to its intracellular effect. The results are discussed in relation to the Leishmania survival mechanism inside the host macrophages and its pathogenicity.