The invention relates to the pentameric form of P protein complex, P0( 197-316 )-(P1-P2) 2 of Plasmodium falciparum defined as Sequence 1 and shown in Fig. 1 , showing immunostimulating properties. The invention relates to the method of obtaining said antigen, comprising the method of protein overexpression with the use of the expression vector characterized in that said expression vector uses said expression cassette containing three gene polycistronic system encoding P protein complex according to the invention and purification is performed with the aid of affinity chromatography according to the invention. The invention relates also to the expression cassette as the component of the expression vector used according to the method described above, defined as Sequence 2 and shown in Fig. 2 , characterized in that the expressed sequence is the three gene polycistronic system, of which every gene contains the separate regulatory RBS sequences and the linker sequences and the P0 protein fragmend is N-terminally fused to the GST protein.
