Evaluation of Merocyanine 540-Sensitized Photoirradiation as a Method for Purging Malarially Infected Red Cells from Blood

Abstract

The photosensitizing dye merocyanine 540 (MC 540) was evaluated as a means for purging malarially infected red cells from murine blood using the rodent malarial pathogens, Plasmodium yoelii and Plasmodium berghei, as models of human malaria. Malarially infected red cells bound more MC 540 and were more sensitive to MC540-sensitized photoirradiation than were noninfected erythroid cells. Extracorporeal exposure of infected red cells to the dye and white light prevented the transmission of the disease in a transfusion model. P. berghei-infected red cells were more resistant to the antimalarial activity of MC 540 than were P.yoelii-infected cells, presumably because P. berghei preferentially infects reticulocytes whereas P.yoelii infects mature red cells. The possibility of using photoirradiation sensitized by MC 540 or related dyes to purge malarially infected donor blood is discussed.