Abstract: 　AIM: To sequence and analyse a cDNA clone CO111 , reacting with immune sera obtained from rabbits immunized with Plasmodium falciparum and one McAb against P falciparum. METHODS: cDNA clone was amplified by PCR. The PCR product was purified and polished with Klenow enzyme and ligated into the M13mp18 vector (digestd by SamI) and then transformed into E coli JM109. The positive recombinant was screened out by PCR and sequenced by the PRISM Dye Primer Sequencing Kit(ABI).The sequence was analyzed by the program from Geneva University and was compared by GenBank of EMBL. RESULTS: The nucleotide sequence of this cDNA clone contains an open reading frame of 233 bp, which encodes a predicted polypeptide of 77 amino acid residues. The ratio between A+T and G+C is 3.16. The polypeptide is highly hydrophilic and flexible. Comparison among cDNA of P falciparum from GenBank of EMBL showed that no sequence identical to this cDNA was found. CONCLUSION: A novel cDNA clone reacted with the antibodies against P falciparum was isolated.

Key words: Plasmodium falciparum, CO111, antigen, hydrophilicity, flexibility