Antimicrobial peptide delivery strategies: use of recombinant antimicrobial peptides in paratransgenic control systems.

Antimicrobial peptides (AMP's) are small peptides that have evolved as part of an innate cell defense mechanism in many organisms. We are currently developing methodologies to use these molecules to control the transmission of vector borne diseases utilizing a paratransgenic strategy. In this approach, symbiotic or commensal microbes of host insects are transformed to express gene products that interfere with pathogen transmission. These genetically altered microbes are re-introduced back to the insect where expression of the engineered molecules decreases the host's ability to transmit the pathogen. In previous work, we demonstrated that the paratransgenic expression of the AMP, cecropin A, by transformed microbes residing in the midgut of the reduviid bug, reduced carriage of the parasite, T. cruzi, substantially. In more recent work, we reported a dramatic increase in parasite killing efficiency when AMP's are used in combination. Further, the AMP concentrations required for parasite killing are decreased by at least 10-fold. In this review, we discuss the feasibility of utilizing other AMP's, individually or in combination, as effector molecules to control the transmission of leishmania parasites by sand flies and to control Vibriosis, a highly devastating disease in shrimp mariculture.

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