Differential synthesis of bacteria-induced proteins of Manduca sexta larvae and pupae

The range of inducible antibacterial and other associated haemolymph proteins in Manduca sexta larvae and pupae was examined by high resolution two-dimensional (2D) isoelectric focusing-polyacrylamide gel electrophoresis. Twenty-two major inducible proteins were consistently resolved on gels of haemolymph from bacteria-injected larvae. Haemolymph from bacteria-injected pupae showed a different pattern of induced proteins. The proteins of the two stages include those which (i) are induced in both stages, (ii) those which are exclusively induced in either larvae or pupae, (iii) those which are inducible in larvae, but consititutively present in pupae, and, (iv) those which are induced in larvae, and which are present at intermediate levels but may be induced to higher levels in pupae.The antibacterial activity of the haemolymph from larvae and pupae was compared on acidpolyacrylamide gels, and the apparent M_r and pI of the inducible proteins determined. Certain of the inducible proteins appear to resemble the cecropin and attacin proteins of Hylophora cecropia.