Cecropins are a family of anti-microbial peptides and produced from the silkworm species as a humoral immune response. These peptides such as cecropins A, B, and D consist of 35-37 amino acids with highly homologous sequences. Their structures contain N- and C-terminal a-helices linked by pro-23 and gly-24 hinge region. They show the ability to kill the bacteria by forming ion selective channels in the lipid bilayers. In the present studies, we also found that these peptides perform the efficacy to against various human leukemia lymphocytes [italic]in [italic]vitro. The results show that the IC₅₀s of cecropin A are 30-40 μM by trypan blue and MTT assays. While, the IC₅₀ of normal lymphocyte is six to sixteen-fold higher than that of the leukemia cancer cells. This implies that cecropin...[ Read more ]

Cecropins are a family of anti-microbial peptides and produced from the silkworm species as a humoral immune response. These peptides such as cecropins A, B, and D consist of 35-37 amino acids with highly homologous sequences. Their structures contain N- and C-terminal a-helices linked by pro-23 and gly-24 hinge region. They show the ability to kill the bacteria by forming ion selective channels in the lipid bilayers. In the present studies, we also found that these peptides perform the efficacy to against various human leukemia lymphocytes [italic]in [italic]vitro. The results show that the IC₅₀s of cecropin A are 30-40 μM by trypan blue and MTT assays. While, the IC₅₀ of normal lymphocyte is six to sixteen-fold higher than that of the leukemia cancer cells. This implies that cecropin A _ can be developed as a new type of anti-cancer drug. However, the 1C₅₀ of cecropin A may be too high to be used as a drug presently. Alternatively, it can be combined with other commercially available anti-cancer agents to increase its effect. The results indicate that the combination of cecropin A with 5-Fu or Ara-c anti-cancer agent shows the supra-additivity. This hints that these mixtures can be better drugs for chemotherapy in the future.

With the potential applications of cecropin A possessing both functions of anti-bacteria and anti-cancer in agriculture and medicine, a production in large quantity is necessary. In this study, preliminary step, production of cecropin A antibody was generated and purified. It will be used in the near future to identify the peptides produced by recombinant DNA technology. The results show that the maximum titer of cecropin A antibody by ELISA was about 1:51200 at the fifth injection and five-fold higher after the purification by Protein A Sepharose CL-4B column. This antibody was further confirmed by SDS-polyacrylamide gel and western-blotting.