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Plasmodium falciparum malaria blood stage parasites preferentially inhibit macrophages with high phagocytic activity[Note 1. The views of the authors do not purport to ...]
Author(s) -
LEITNER WOLFGANG W.,
KRZYCH URSZULA
Publication year - 1997
Publication title -
parasite immunology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.795
H-Index - 75
eISSN - 1365-3024
pISSN - 0141-9838
DOI - 10.1046/j.1365-3024.1997.d01-188.x
Subject(s) - phagocytosis , malaria , biology , immunology , immune system , plasmodium falciparum , macrophage , antigen , monocyte , population , parasite hosting , plasmodium (life cycle) , microbiology and biotechnology , in vitro , medicine , biochemistry , environmental health , world wide web , computer science
Exposure to malaria blood stage antigens results in several defects of macrophages/monocytes one of which is an irreversible reduction of phagocytic activity. In the present study we analysed phagocytic activity of subpopulations of human monocyte‐derived‐macrophages (MDM) based on the capacity of individual cells to ingest FITC‐labelled microbeads. The results demonstrate that malaria infection affected predominantly MDM subpopulations with high level of phagocytosis. This population decreased during parasitaemia, however, during recovery from the infection the highly phagocytic cells replaced the damaged cells. The exposure of MDM cultures to blood stage antigens showed that the highly active macrophages from persons with active malaria infection decreased further, while the population increased during recovery. Furthermore, we observed that while ingestion of a few parasitized RBC (3 schizonts) stimulated phagocytosis, larger amounts or longer exposure periods eventually paralysed the entire phagocytic system. Accordingly, by selectively blocking actively phagocytizing macrophages, the malaria parasite prevents both specific and non‐specific immune responses, which are initiated by macrophages as phagocytes and professional antigen presenting cells.