A PROTEIN WITH PROTECTIVE PROPERTIES AGAINST THE CELLULAR DEFENSE REACTIONS IN INSECTS

The molecular mechanism of how insects recognize intruding microorgani sms and parasites and distinguish them from own body structures is not well known. We explored evolutionary adaptations in an insect parasit oid host interaction to identify components that interfere with the re cognition of foreign objects and cellular encapsulation. Because some parasitoids provide protection for the developing wasp in the absence of an overt suppression of the insect host defense, we analyzed the su rface of eggs and symbiotic viruses for protective properties. Here we report on the molecular cloning of a 32-kDa protein (Crp32) that is o ne of the major protective components. It is produced in the calyx cel ls of the female wasp ovaries and attached to the surface of the egg a nd other particles including polydnaviruses. The recombinant protein c onfers protection to coated objects in a cellular encapsulation assay suggesting that a layer of Crp32 may prevent cellular encapsulation re actions by a local inactivation of the host defense system.