Expression in Escherichia coli and immunological characterization of a hybrid class 1-P64k protein from Neisseria meningitidis

Class 1 outer membrane protein of Neisseria meningitidis induce bactericidal antibodies, have been used for the classification of meningococci in subtypes, and combinations of these epitopes have been considered for a new vaccine. Attempts to express Class 1 proteins in Escherichia coli have until now been unsuccessful; possibly due to the lethality of these proteins. We have previously described a new high molecular weight protein (P64k), present in all serogroups and serotypes of N. meningitidis tested. Here, we report the expression of a 219 aminoacid fragment of the P1.15 proteins as a fusion with the meningococcal P64k in two E. coli strains. It was easily purified and it was immunogenetic in mice, capable of eliciting bactericidal antibodies.