The effects of chemical modification on the adhesion of Plasmodium falciparum-infected and uninfected erythrocytes.
Binding of Plasmodium falciparum-infected erythrocytes (PE) to endothelial cells is mediated by the erythrocyte-membrane protein, band 3-related adhesin. To determine its role, the binding of infected cells treated with various chemical modifiers was investigated. Binding was inhibited by a lysine modifier (4,4'-diisothiocyanostilbene-2,2'-disulfonate (DIDS)) known to specifically bind to band 3, another lysine modifier (trinitrobenzene sulfonic acid), a tyrosine modifier (sodium iodide in conjunction with lactoperoxidase, hydrogen peroxide) and oxidants (diamide, sodium periodate and ADP-chelated ferric ion), but binding was unaffected by the histidine modifier (diethylpyrocarbonate) and the arginine modifier (phenyl glyoxyl monohydrate). To artificially expose the band 3-related adhesin, uninfected erythrocytes were treated with acridine orange or loaded with calcium. These cells bound to C32 amelanotic melanoma cells, were immunostained with a monoclonal antibody that specifically binds to the band 3-related adhesin on PE, and the binding was inhibited by this monoclonal antibody. The binding of acridine orange-treated and calcium-loaded uninfected erythrocytes, could also be blocked by DIDS. In the case of acridine orange-treated erythrocytes, the patterns of the effects of the chemical modification on binding were consistent with that of PE except for tyrosine modification. These results demonstrate that the band 3-related adhesin, even in the absence of parasite-encoded proteins, contributes to PE adhesion.
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Department of Biology, University of California, Riverside 92521, USA.
Sherman
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D017878:4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid / Q000494:pharmacology; D000165:Acridine Orange / Q000494:pharmacology; D000818:Animals; D001457:Anion Exchange Protein 1, Erythrocyte / Q000187:drug effects / Q000502:physiology*; D002118:Calcium / Q000494:pharmacology; D002448:Cell Adhesion / Q000187:drug effects; D004047:Diethyl Pyrocarbonate / Q000494:pharmacology; D004912:Erythrocytes / Q000737:chemistry / Q000187:drug effects* / Q000469:parasitology; D019085:Fluorescent Antibody Technique, Direct; D006801:Humans; D007155:Immunologic Factors; D017613:Iodine Compounds / Q000494:pharmacology; D016877:Oxidants / Q000494:pharmacology; D010963:Plasmodium falciparum; D014302:Trinitrobenzenesulfonic Acid / Q000494:pharmacology
D001457:Anion Exchange Protein 1, Erythrocyte; D007155:Immunologic Factors; D017613:Iodine Compounds; D016877:Oxidants; D014302:Trinitrobenzenesulfonic Acid; D000165:Acridine Orange; D004047:Diethyl Pyrocarbonate; D017878:4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid; D002118:Calcium