OxyFile #134

The Lancet
December 25, 1982
pp. 1431-1433


Hypothesis

A Radical Interpretation of Immunity to Malaria Parasites


Asexual forms of malaria parasites in erythrocytes are sensitive to 
oxidant stress.  Immunity to these parasites is thymus-dependent and 
may be mediated by the binding of effector cells (macrophages or 
natural killer cells) to the surface of parasitised cells, with 
concomitant production of the superoxide anion (O2).  This can lead 
to degeneration of parasites in erythrocytes.  Antibodies can 
facilitate the binding of effector cells to parasites in 
erythrocytes, reinforcing the effects of cell-mediated immunity.  
Plasmodium falciparum is more sensitive to oxidant stress in human 
erythrocytes with abnormal haemoglobins and glucose-6-phosphate-
dehydrogenase deficiency than in normal erythrocytes.  Thus cell-
mediated immune responses, by producing oxidant stress, could act 
synergistically with these inherited traits to increase the chances 
of survival of children during the dangerous years of first exposure 
to malaria.