Studies on the role of host serum in the retention of malarial sporozoites by isolated perfused rat liver.

The binding of host serum components to malarial sporozoites has been proposed as a mechanism for the specific phagocytic uptake of these parasites, and hence the specificity of host infection (SCHULMAN et al., 1981). We therefore observed the kinetics of uptake of sporozoites of Plasmodium yoelii nigeriensis and P. gallinaceum by isolated perfused rat livers in the presence of homologous or heterologous sera. In the homologous system (P. y. nigeriensis sporozoites in rat serum) sporozoite uptake followed zero order kinetics, total uptake being achieved within 20 min. Substitution of rat serum with either chick or foetal calf serum did not change the pattern of uptake. The uptake of P. gallinaceum sporozoites in rat serum was similar to that of P. y. nigeriensis. Further, the uptake of P. y. nigeriensis sporozoites was the same in the absence of serum as in its presence. These observations suggest that the specific attachment of serum components to homologous malaria sporozoites is unlikely to be responsible for the specificity of host infection.