Molecular cloning and sequencing of the circumsporozoite protein gene fromPlasmodium falciparum strain FCC-1/HN and expression of the gene in mycobacteria

Mycobacterium bovis bacillus Calmette-Guerin (BCG) has been used as a live bacterial vaccine to immunize more than 2 billion people against tuberculos is. In an attempt to use this vaccine strain as a vehicle for protective an tigens, the Plasmodium falciparum gene from strain FCC-1/HN encoding circum sporozoite protein (CSP) was amplified from the P. falciparum genome, seque nced, and expressed in M. bovis BCG under the control of an expression cass ette carrying the promoter of heat shock protein 70 (HSP70) from Mycobacter ium tuberculosis. The recombinant shuttle plasmid pBCG/CSP was introduced i nto mycobacteria by electroporation, and the recombinant mycobacteria harbo ring pBCG/CSP could be induced by heating to express CSP; the molecular mas s of recombinant CSP was about 42 kDa. This report of expression of the alm ost-full-length P. falciparum CSP gene in BCG provides scientific evidence for the application of the HSP70 promoter in expressing a foreign gene in B CG and in development of BCG as a multivalent vectoral vaccine for malaria.