Purified Plasmodium and Vaccine Compositions

A method for purification of metabolically active Plasmodium sporozoites, said method comprising;

• (a) providing an aqueous pre-purification preparation comprising sporozoites and attendant non-sporozoite material;
• (b) passing said sporozoite preparation sequentially through a set of size exclusion filters comprising:
• (i) a first exclusion filter with a pore size capable of retaining attendant material larger than 10 microns but allowing passage of said sporozoites;
• (ii) a second exclusion filter with a pore size capable of retaining attendant material larger than about 1.2 microns but allowing passage of said sporozoites;
• and
• (iii) a third membrane filter with a pore size capable of passing material 1.2 microns or smaller and allowing passage of said sporozoites;
• (c) collecting substantially purified sporozoites on a collecting filter with a pore size capable of retaining said sporozoites;
• and
• (d) removing the collected substantially purified sporozoites from the collecting filter, thereby producing a purified sporozoite preparation that is substantially free of attendant non-sporozoite material.