Impairment of macrophage functions after ingestion of Plasmodium falciparum-infected erythrocytes or isolated malarial pigment.
Open Access
- 1 October 1992
- journal article
- Published by Rockefeller University Press in The Journal of Experimental Medicine
- Vol. 176 (4) , 1033-1041
- https://doi.org/10.1084/jem.176.4.1033
Abstract
Human monocyte-derived macrophages ingest diamide-treated red blood cells (RBC), anti-D immunoglobulin (Ig)G-opsonized RBC, or Plasmodium falciparum ring-stage parasitized RBC (RPRBC), degrade ingested hemoglobin rapidly, and can repeat the phagocytic cycle. Monocytes fed with trophozoite-parasitized RBC (TPRBC), which contain malarial pigment, or fed with isolated pigment are virtually unable to degrade the ingested material and to repeat the phagocytic cycle. Monocytes fed with pigment display a long-lasting oxidative burst that does not occur when they phagocytose diamide-treated RBC or RPRBC. The phorbol myristate acetate-elicited oxidative burst is irreversibly suppressed in monocytes fed with TPRBC or pigment, but not in monocytes fed with diamide-treated or IgG-opsonized RBC. This pattern of inhibition of phagocytosis and oxidative burst suggests that malarial pigment is responsible for the toxic effects. Pigment iron released in the monocyte phagolysosome may be the responsible element. 3% of total pigment iron is labile and easily detached under conditions simulating the internal environment of the phagolysosome, i.e., pH 5.5 and 10 microM H2O2. Iron liberated from pigment could account for the lipid peroxidation and increased production of malondialdehyde observed in monocytes fed with pigment or in RBC ghosts and liposomes incubated at pH 6.5 in presence of pigment and low amounts of H2O2. Removal of the labile iron fraction from pigment by repeated treatments with 0.1 mM H2O2 at pH 5.5 reduces pigment toxicity. It is suggested that iron released from ingested pigment is responsible for the intoxication of monocytes. In acute and chronic falciparum infections, circulating and tissue-resident phagocytes are seen filled with TPRBC and pigment particles over long periods of time. Moreover, human monocytes previously fed with TPRBC are unable to neutralize pathogenic bacteria, fungi, and tumor cells, and macrophage responses decline during the course of human and animal malaria. The present results may offer a mechanistic explanation for depression of cellular immunity in malaria.Keywords
This publication has 38 references indexed in Scilit:
- Why do some African children develop severe malaria?Parasitology Today, 1991
- Clustering of integral membrane proteins of the human erythrocyte membrane stimulates autologous IgG binding, complement deposition, and phagocytosis.Journal of Biological Chemistry, 1991
- Modification of host cell membrane lipid composition by the intra-erythrocytic human malaria parasite Plasmodium falciparumBiochemical Journal, 1991
- Desferrioxamine as a lipid chain‐breaking antioxidant in sickle erythrocyte membranesFEBS Letters, 1990
- Oxidative stress and the redox status of malaria-infected erythrocytes.1990
- Innate resistance to malaria: the intraerythrocytic cycle.1990
- Malaria and red cell genetic defects.1989
- Changes in the superoxide anion generating capacity and respiratory burst enzymes of peripheral blood monocytes of monkeys during acute Plasmodium knowlesi infectionParasite Immunology, 1989
- Synchronization of Plasmodium falciparum Erythrocytic Stages in CultureJournal of Parasitology, 1979
- A Rapid and Sensitive Method for the Quantitation of Microgram Quantities of Protein Utilizing the Principle of Protein-Dye BindingAnalytical Biochemistry, 1976