Abstract:

In order to analyze the antifungal activity and immunogenicity of antifungal peptide Drosomycin（Drs） and its isoforms, Drs-lC and Drs-lE, from Drosophila melanogaster, their antibodies were prepared by two ways. In the first way, Drs, Drs-lC and Drs-lE were respectively fused with afgf gene. In the second way, Drs and Drs-lE were respectively linked into multi-copy genes of Drs and Drs-lE tandem in the same direction. The recombinant plasmids pET-afgf-Drs, pET-afgf-C and pET-afgf-E were constructed through the first way, while pRSET-2Drs, -4Drs, -6Drs and pRSET-2E, -4E, -6E were constructed through the second way. They were then transformed into E. coli BL21（DE3）plysS. After purification, the fused proteins afgf-Drs, afgf-C, afgf-E and the concatamer proteins of 4 Drs, 4 Drs-lE were used for preparation of the antiserums by immunizing mice. The results of Western-blot immunogenicity showed that Drs and its isoforms had strong antigen immune reactions with their according antiserums. Cross-reactions between them were also found. These results suggested that they might have the similar main antigen sites. We so inferred that there is no relationship between the main antigen sites and activity sites. The small difference of their structures may be the main  mechanism causing the functional divergence of their antifungal activity.

Key words: Drosophila melanogaster, antifungal peptide, Drosomycin, isoforms, immunogenicity, antifungal activity