Drosophila antibacterial protein, cecropin A, differentially affects non-bacterial organisms such as Leishmania in a manner different from other amphipathic peptides.
The effects of the antibacterial protein Drosophila cecropin A on developmental forms of Leishmania were compared with the effect of Hyalophora cecropin A in vitro. Both cecropins had a potent lytic activity on the promastigotes at concentrations not far from those occurring in vivo in the respective insect. Drosophila cecropin A had strong differential effects on the two maturation forms of Leishmania aethiopica at high concentrations: inhibiting intracellular amastigotes and stimulating extracellular promastigotes to take up thymidine. Hyalophora cecropin A also inhibited amastigotes by up to 50% at concentrations of 0.250 mg/ml, and inhibited promastigotes at high concentrations but had no enhancing effects at any of the concentrations tested. In contrast to the results with Leishmania, Drosophila cecropin A had no discernible effect on any developmental stage of P. falciparium and showed no lytic effects on haemocytes. The two enantiomers of a synthetic amphipathic peptide, D- and L-KALA, were also tested. D- and L-KALA had some in vitro antimalarial effects at 0.025 and 0.05 mg/ml respectively but both forms were haemolytic at 0.1 mg/ml. Potential uses of naturally occurring proteins and their derivatives in the control of insect born infections and topical use of cecropins against leishmaniasis are discussed.
Akuffo
H
H
Microbiology and Tumor Biology Centre, Karolinska Institute, 17177 Stockholm, Sweden.
Hultmark
D
D
Engstöm
A
A
Frohlich
D
D
Kimbrell
D
D
D000818:Animals; D000890:Anti-Infective Agents / Q000494:pharmacology; D023181:Antimicrobial Cationic Peptides; D000981:Antiprotozoal Agents / Q000494:pharmacology*; D001345:Autoradiography; D004330:Drosophila; D004912:Erythrocytes / Q000469:parasitology; D006801:Humans; D007891:Leishmania / Q000187:drug effects*; D010455:Peptides / Q000494:pharmacology*; D010963:Plasmodium falciparum / Q000187:drug effects
D000890:Anti-Infective Agents; D023181:Antimicrobial Cationic Peptides; D000981:Antiprotozoal Agents; D010455:Peptides; C031161:cecropin A