A 33-35 kDa circulating antigen from Plasmodium falciparum

Isolation and characterisation of Plasmodium falciparum (Welch, 1897) solub le antigens from infected patient plasma, Western blotting, thermal stabili ty and ELISA assays using hyperimmune IgG-antimalaria antibodies was the ma in objective of this work. A circulating antigen of approximately Mr 33-35 kDa with good specificity and antigenicity, in the plasma of malarial patie nts was shown. Heating at 100 degreesC did not destroy its antigenicity. Wh en fractions highly enriched in the 33-35 kDa proteins were used in ELISAs, a seroreactivity in plasma obtained from primary-infected individuals was found. Controls from normal patients were always negative. The antigenic ch aracteristics suggest that it may be included within the group of new descr ibed Plasmodium soluble antigens.