Monoclonal auto-antibodies and sera of autoimmune patients react with Plasmodium falciparum and inhibit its in vitro growth.
The reactivity to overlapping decapeptides based on sequences of human band 3 protein was determined for 24 rabbit serum samples. A high percentage of the sera recognized sequences of amino acid 650-670, as well as several other sequences representing putative exofacial regions of the band 3 protein. When sera were used to stain immunofluorescently human erythrocytes, some of which were infected with P. falciparum, those samples that predominantly reacted with amino acids 650-670 stained P. falciparum-infected red cells, whereas those that reacted with other regions of band 3 stained all erythrocytes. A positive correlation was found between anti-band 3 reactivity and the capacity of a serum to inhibit the cytoadherence of P. falciparum-infected erythrocytes to C32 amelanotic melanoma cells. Also, some rabbit sera immunoprecipitated a high-molecular-weight protein from extracts of surface iodinated P. falciparum-infected red cells.