MALARIAL IMMUNODEPRESSION INVITRO - ADHERENT SPLEEN-CELLS ARE FUNCTIONALLY DEFECTIVE AS ACCESSORY CELLS IN RESPONSE TO HORSE ERYTHROCYTES

The basis for the depressed response of malarial infected mice to horse red blood cells (HRBC) was studied in vitro. The adherent spleen cells from infected mice show the following characteristics: they are defective in their ability to allow nonadherent spleen cells of normal and infected mice to respond to HRBC, whereas a response does occur with adherent spleen cells from normal mice; they do not suppress the response of unfractionated spleen cells from normal mice to HRBC; and they contain phagocytic cells as measured by the uptake of neutral red in numbers which are of the same order of magnitude as in adherent spleen cells from normal mice, but which are unable to take up HRBC. A splenic adherent cell, probably the macrophage, is apparently functionally defective as an accessory cell in the response to HRBC of mice infected with Plasmodium berghei yoelii.