Variations in expression of markers by populations of adherent cells from Trypanosoma cruzi-infected mice

The kinetics of differentiation and maturation of phagocytic cells during the acute and chronic stages of experimental Chagas' disease was examined by monitoring changes in expression of peroxidase (PO), nonspecific esterase (NSE), C3b receptors (CR), Fc receptors (FcR), and phagocytic ability of cells in the blood, spleen, and peritoneal cavity. The significant changes recorded in the blood were: marked increases in the percentages of CR- and FcR-positive adherent cells during both the acute and chronic phase; Ia-positive cells increased two-fold in the acute period and remained elevated in the chronic stage. In the spleen, the major alterations recorded during both the acute and chronic stages were: two- to three-fold increases in the percentages of NSE- and PO-positive adherent cells and three- to four-fold increases in the proportions of CR- and FcR-positive cells. In addition, Ia-positive cells increased from 70% to approximately 90% of the adherent cell population. In the peritoneal cavity, a two- to four-fold elevation in the percentages of both PO- and NSE-positive cells was observed. The number of Ia-positive cells increased from 10% before infection to 85-90% during the acute phase and to 96-98% during the chronic period. All of the changes described above occurred in the absence of noticeable increases in phagocytic ability except for an elevation in the percentage of circulating latex-ingesting cells seen during chronicity. These results indicate that infection with Trypanosoma cruzi alters the pathways of differentiation of cells of the mononuclear phagocyte lineage.