Peritrophins of adult dipteran ectoparasites and their evaluation as vaccine antigens

Several peritrophins of larvae of Lucilia cuprina (sheep blowfly) have demo nstrated potential as vaccine antigens, and some have been characterised an d cloned. These proteins are tightly associated with the peritrophic matrix , a chitinous tube or sac lining the lumen of the gut of most insects. The peritrophins require strong denaturants for their removal from peritrophic matrix. We now report the preliminary characterisation of peritrophins of t he adult stage of L. cuprina and Haematobia irritans exigua (buffalo fly). Similar SDS-PAGE profiles were obtained for proteins extracted in SDS or ur ea from isolated adult peritrophic matrices of both species. Radioiodinatio n of urea-extracted peritrophins improved sensitivity, indicating numerous proteins of 15-75 kDa. Direct radioiodination of L. cuprina peritrophic mat rix preferentially labelled high molecular weight complexes and proteins of 80-90 kDa. Two-dimensional gel analyses of a urea extract of adult L. cupr ina peritrophic matrix revealed that most proteins were moderately acidic. Antibodies produced against SDS-extracted peritrophins, or against sonicate d peritrophic matrices of these two flies were crossreactive. The sera also appeared to recognise SDS-extracted components of Triton X-100 treated and washed adult peritrophic matrix of the mosquito, Aedes vigilax (Skause). T his profile altered as the peritrophic matrix matured. In concordance with extracts from the adult L. cuprina and H.i. exigua peritrophic matrices, pr oteins in the 50-75 kDa region were immunodominant. The vaccine potential o f the peritrophins of these Diptera were examined following vaccination of cattle and rabbits with adult H.i. exigua or L. cuprina peritrophins. When the adult life stages of H.i. exigua or two mosquitoes, A. vigilax and A. a egypti (Linnaeus), were fed on the sera or blood of vaccinated hosts, there were no detrimental effects to any life cycle stages of these Diptera. (C) 1999 Australian Society for Parasitology Inc. Published by Elsevier Scienc e Ltd. All rights reserved.