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

Transferrin-binding proteins from Neisseria meningitidis vary among di fferent isolates. We have identified and studied a hypervariable regio n adjacent to the carboxyl-end of the transferrin-binding domain of th e Tbp2 molecule. The tbp2 genes from six strains of N. meningitidis we re cloned and sequenced in this particular region. Sequence analysis o f these regions a along with five other sequences available from patho genic Neisseria showed a common organisation of seven highly variable nucleotide stretches interspersed with six conserved nucleotide stretc hes. The variable regions correlated with the location of immunoreacti ve epitopes in polyclonal antisera raised to transferrin-binding prote ins identified by peptide pin technology, Sequence analysis suggested a mosaic-like organisation of the tbp2 genes. Taken together, these da ta suggest that the antigenic variation in this part of the protein ma y result from a strong host immune pressure.