Plasmodium falciparum (human malaria)-induced modifications in human erythrocyte band 3 protein

A monoclonal antibody, 1C4, was produced which recognizes a 65 kDa protein that is localized to the plasma membrane of human erythrocytes infected with Plasmodium falciparum. By immunofluorescence the antigen was visualized as dots on the surface of the infected cell. The 65 kDa protein was present in 4 strains of diverse geographical origin, and in erythrocytes infected with a knobless strain. The 65 kDa protein was insoluble in non-ionic detergents, but was partly soluble in SDS and some high (1 M) salt solutions. The 65 kDa protein is recognized by antibodies specific for the cytoplasmic domain and the N-terminal side of the membrane-spanning region of human band 3, but was not recognized by an antibody specific to the C-terminal side of the membrane-spanning region. The results of treatment of the 65 kDa protein with trypsin and chymotrypsin are consistent with the 65 kDa protein being a truncated and covalently modified band 3 molecule which consists of the first 540 amino acids of human band 3.