HOST UROKINASE-TYPE PLASMINOGEN-ACTIVATOR PARTICIPATES IN THE RELEASEOF MALARIA MEROZOITES FROM INFECTED ERYTHROCYTES

Malaria infection of red blood cells is associated with plasminogen ac tivation. Surface immunfluorescence and immunoprecipitation experiment s, using specific polyclonal and monoclonal antibodies raised against human urokinase, demonstrate that this activity is due to the binding of host urokinase-type plasminogen activator to the surface of erythro cytes infected by mature forms of Plasmodium falciparum malaria parasi tes. Depletion of urokinase from the culture medium leads to the inhib ition of merozoite release and the accumulation of segmenter-infected erythrocytes; this inhibition is reversed by the addition of human sin gle-chain or two-chain urokinase. These findings are consistent with h ost urokinase being involved in the process of merozoite release from the red blood cell. (C) 1997 Elsevier Science B.V.