VARIABLE SEQUENCES IN A MOSAIC-LIKE DOMAIN OF MENINGOCOCCAL TBP2 ENCODE IMMUNOREACTIVE EPITOPES

Transferrin-binding proteins from Neisseria meningitidis vary among different isolates. We have identified and studied a hypervariable region adjacent to the carboxyl-end of the transferrin-binding domain of the Tbp2 molecule. The tbp2 genes from six strains of N. meningitidis were cloned and sequenced in this particular region. Sequence analysis of these regions a along with five other sequences available from pathogenic Neisseria showed a common organisation of seven highly variable nucleotide stretches interspersed with six conserved nucleotide stretches. The variable regions correlated with the location of immunoreactive epitopes in polyclonal antisera raised to transferrin-binding proteins identified by peptide pin technology, Sequence analysis suggested a mosaic-like organisation of the tbp2 genes. Taken together, these data suggest that the antigenic variation in this part of the protein may result from a strong host immune pressure.