Evidence for a relationship between chloroquine and complement from studies with lymphocyte mitogens: possible implications for the mechanism of action of chloroquine in disease.
Chloroquine increases the inhibition of cultured lymphocytes by high concentrations of phytohemagglutinin (PHA) or concanavalin A (Con A). The inhibition is also increased by complement. Thus chloroquine and complement have similar effects. Time-course studies show that chloroquine increases the rate of onset of the complement-dependent inhibition. In serum preheated to inactivate complement, chloroquine can partially simulate the effect of complement. It is suggested that at certain stages in malaria or autoimmune disease the rate of clearance of parasitized erythrocytes or autoreactive lymphocytes is limited by the concentration of complement. Under these conditions a drug such as chloroquine, which could enhance or simulate the action of complement, might be of therapeutic value.
D000818:Animals; D001327:Autoimmune Diseases / Q000188:drug therapy; D002478:Cells, Cultured; D002738:Chloroquine / Q000494:pharmacology* / Q000627:therapeutic use; D003165:Complement System Proteins; D003208:Concanavalin A / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D005260:Female; D006358:Hot Temperature; D006801:Humans; D037102:Lectins / Q000494:pharmacology; D008213:Lymphocyte Activation / Q000187:drug effects; D008214:Lymphocytes / Q000187:drug effects*; D008288:Malaria / Q000188:drug therapy; D051381:Rats
D037102:Lectins; D003208:Concanavalin A; D002738:Chloroquine; D003165:Complement System Proteins