Changes in Host-cell Preferences in Malarial Parasites and Their Relation to Splenic Reticular Cells

Abstract

When either sporozoites or erythrocytic stages of Plasmodium gallinaceum were introduced intraven. into chicks the 1st exoerythrocytic stages were observed in the reticular cells of the Schweigger-Seidel sheaths of the spleen. Likewise following intraven. inoculation of erythrocytic stages of P. lophurae and P. fallax the 1st exoerythrocytic stages were observed in similar cells of turkeys, and similarly for P. cathemerium in canaries. Since the inoculated erythrocytic stages had ready access to the vascular endothelial cells from the moment of their inoculation but did not invade these cells until after they had produced exoerythrocytic stages in the splenic reticular cells, it appears likely that they were changed in some way by their residence in the splenic cells. Although the mechanism of these changes (termed "conversions") is not yet understood, the most plausible hypothesis appears to be that antibodies produced within the splenic reticular cells bring about changes in the potentialities of the parasites for living in the different types of host cells.