ATTEMPTED ISOLATION OF THE GENE ENCODING THE 21-KD PLASMODIUM-BERGHEIOOKINETE TRANSMISSION-BLOCKING ANTIGEN FROM PLASMODIUM-YOELLI AND PLASMODIUM-VIVAX

The 21kD ookinete antigen of Plasmodium berghei (Pbs 21) has been show n to elicit art effective and long lasting transmission blocking immun e response in mice. Having cloned and sequenced this antigen (Paton et al. 1993) the sequence was compared to the genes of the same family p reviously identified in P. falciparum, P. gallinaceum (Kaslow et al. 1 989) and P. reichenowi (Lal et al. 1990). Four consented areas were id entified in this comparison, to which degenerate oligonucleotides were designed. PCR amplification and screening of genomic libraries was th en carried our using these oligonucleotides. The P. yoelii gene was su ccessfully cloned and a number of novel P. vivax genes identified but the P. vivax homologue of Pbs21 remains elusive.