Identification of two major families of transferrin receptors among Neisseria meningitidis strains based on antigenic and genomic features

Abstract

The transferrin receptor or transferrin-binding proteins (Tbps) of 50 strains of Neisseria meningitidis belonging to different serogroups were examined by Western blotting using two rabbit antisera raised against Tbp purified from N. meningitidis strains B16B6 and M982. On the basis of the reactivity of Tbp2 with the antisera two patterns were observed and allowed the classification of 74% of the strains in group I (M982-like strains) and 26% in group II (B16B6-like strains). Southern blot analysis was performed on the genomic DNA of 16 meningococcal strains and showed that under stringent conditions, the tbp2 probes were specific for each group identified. Both immunological and genomic analyses have led to the identification within N. meningitidis strains of two major families distinguished on the basis of the characteristics of Tbp2 molecules, independently of serogroup, type or subtype.

Gonococcal transferrin-binding protein 2 facilitates but is not essential for transferrin utilization

“…The two classes of meningococcal Tbp2 are defined by their molecular weights, antigenic heterogeneity (37), and sequence similarity (22). Tbp2 from gonococcal strain FA19 is most similar to Tbp2 from the meningococcal strain M982 (22), sharing 71% identity and 79% similarity.…”

“…The University of Wisconsin Genetics Computer Group DNA analysis programs (8) were used to evaluate the sequence data for homology between the two different classes of meningococcal Tbp2 (22,37) and gonococcal Thp2. The program Bestfit generated an identity score of 48% and a similarity score of 65% between Tbp2 in FA19 and meningococcal strain B16B6 (22) and scores of 71% identity and 79% similarity between FA19 and meningococcal strain M982 (22).…”

“…The size of Thp2 varies widely depending on the meningococcal strain examined (41,43). Analysis of antigenic and genomic features of meningococcal Tbp2 variants has prompted the division of this protein into two classes (37). Both meningococcal (41,43) and gonococcal (6) Tbp2 bind Tf after sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis (PAGE) and electroblotting.…”

Characterization of a highly structured domain in Tbp2 from Neisseria meningitidis involved in binding to human transferrin

“…The genes encoding Tbpl and Thp2 have been isolated from two N. meningitidis group B strains, B16B6 and M982 (12), which were chosen for the differences observed in electrophoretic mobilities and antigenic properties of their Tbp2s (16). They were shown to be organized in tandem, tbp2 being followed by tbpl, with an 87-bp intergenic region.…”

Transferrin-Binding Protein B of Neisseria meningitidis : Sequence-Based Identification of the Transferrin-Binding Site Confirmed by Site-Directed Mutagenesis

“…Immunization with TbpB has been shown to elicit a protective immune response in laboratory animals, which has been related to the production of bactericidal antibodies (17,24). Based on genomic and antigenic features of TbpB, meningococcal strains have been classified into two major families: isotype I, containing TbpB with a mass of ϳ68 kDa, and isotype II, harboring TbpB with a mass between 80 and 90 kDa (26).…”