2-DIMENSIONAL STRUCTURE OF THE OPC INVASIN FROM NEISSERIA-MENINGITIDIS

A two-dimensional structural model was devised for the Ope outer membr ane protein invasin which contains 10 transmembrane strands and five s urface-exposed loops. One continuous epitope recognized by three monoc lonal antibodies was localized to the tip of loop 2 by synthetic pepti des and site-directed mutagenesis while a second, discontinuous epitop e recognized by a fourth antibody was localized to loops 4 and 5 by in sertion mutagenesis. These monoclonal antibodies are bactericidal and inhibit adhesion and invasion. Most of the T-cell epitopes defined by Wiertz at al. (1996) were localized to the transmembrane strands. Olig onucleotides encoding a foreign epitope (del) from Semliki Forest viru s were inserted into Bg/II restriction sites created by site-directed mutagenesis. The del epitopes inserted in all five predicted loops wer e recognized on the cell surface of live Escherichia coil bacteria by a monoclonal antibody and are exposed while del epitopes in the N-term inus or three predicted turns were not. The results thus confirm impor tant predictions of the model and define five permissive sites within surface-exposed loops which can be used to insert foreign epitopes.