'NMB1870' is a known surface protein in Neisseria meningitidis expressed across all serogroups. It has three distinct families. Serum raised against a given family is bactericidal within the same family, but is not active against strains which express one of the other two families i.e. intra-family but not inter-family cross-protection. The inventors have found that NMB1870 can be divided into domains, and that not all domains are required for antigenicity. Antigenic domains can be taken from each of the three NMB1870 families and expressed as a single polypeptide chain. The inventors have also found that NMB1870 exposes some of its epitopes in surface loops situated between alpha helices, and that substitution of loop epitopes from one family into the loop position in another family allows chimeric NMB1870 to be produced with multi-family antigenicity. Thus chimeric NMB1870 proteins are provided that comprise portions of NMB1870 from different families.Proces za proizvodnju himerične NMB1870 aminokiselinske sekvence, koji sadrži sledeće korake: (a) poravnavanje prve NMB1870 aminokiselinske sekvence sa drugom NMB1870 aminokiselinskom sekvencom, pri čemu se prva i druga sekvenca razlikuju i iz različitih su NMB 1870 familija, da se dobije par poravnatih sekvenci, (b) odabiranje dela prve aminokiselinske sekvence, počev od amino kiseline a1 navedene prve amino-kiselinske sekvence, sa završetkom kod aminokiseline b1 navedene prve aminokiselinske sekvence, gde deo predstavlja sekvencu površinske petlje (c) odabiranje dela druge aminokiselinske sekvence, počev od amino kiseline a2 navedene druge amino kiselinske sekvence sa završetkom kod amino kiseline b2 navedene druge aminokiselinske sekvence, pri čemu je deo sekvenca površinske petlje, i gde su rezidui a1 i a2 i b1 i b2 poravnati u par poravnatih sekvenci； i (d) zamena navedenog dela prve aminokiselinske sekvence sa pomenutim delom druge amino kiselinske sekvence, čime se obezbeđuje himerična NMB1870 aminokiselinska
