Expression of a functional antibody fragment in the gut of Rhodnius prolixus via transgenic bacterial symbiont Rhodococcus rhodnii

Expression within insects of foreign antiparasitic gene products via microb ial symbionts could be used to prevent transmission of vector-borne pathoge ns to vertebrate hosts. Genetically transformed symbiotic bacteria Rhodococ cus rhodnii expressed functional antibody fragments (rDB3 encoding murine V -H/K which binds progesterone) that were exported into the gut lumen of the triatomine bug Rhodnius prolixus (Hemiptera: Reduviidae), a vector of Chag as disease, Transgenic symbionts were maintained in successive nymphal inst ars and adults of Rhodnius prolixus despite competition with native untrans formed Rhodococcus rhodnii. This is the first description of a functional m ammalian antibody fragment expressed in an insect. Our system is a model fo r constructing paratransgenic insects (insects carrying transformed symbion ts) with compromised ability to transmit pathogens.