Evidence for in vivo but not in vitro expression of a Borrelia burgdorferi outer surface protein F (OspF) homologue

Abstract

Protein export signals from the low-passage 297 strain of Borrelia burgdorferi were cloned as fusions with an Escherichia coli alkaline phosphatase (PhoA) reporter lacking a signal sequence. One PhoA+ clone (BbK2.10-PhoA) was derived from a borrelial lipoprotein. Although the polypeptide encoded by the full-length bbk2.10 gene had 76% similarity and 56% identity to outer surface protein F (OspF) from B. burgdorferi strain N40, antibodies directed against recombinant forms of the two proteins revealed that they were not cross-reactive. The nucleotide sequences of bbk2.10 and ospF from the N40 and 297 strains, respectively, were determined to confirm that the N40 and 297 strains each contained both genes. Southern blot analysis revealed that bbk2.10 is a single-copy gene and that the B. burgdorferi strain 297 and N40 genomes appeared to contain one other gene more closely related to ospF than bbk2.10. It was particularly noteworthy that ospF, but not bbk2.10, was expressed in vitro while B. burgdorferi-infected mice generated antibodies reactive with both lipoproteins. To help confirm that the BbK2.10-reactive antibodies produced by the B. burgdorferi-infected mice were specific for that protein, a second gene, bbk2.11, which hybridized with the ospF probe was cloned; the corresponding polypeptide reacted strongly with OspF antisera but failed to react with BbK2.10-specific antisera. Taken together, these data demonstrate that BbK2.10, BbK2.11, and OspF comprise a B. burgdorferi lipoprotein family and that at least one member (BbK2.10) appears to be expressed only during infection.

A family of genes located on four separate 32-kilobase circular plasmids in Borrelia burgdorferi B31

“…Both of the encoded proteins appear to be related to OspE and OspF, and the genes may constitute a bicistronic locus. Akins et al (1) have cloned a third locus from B. burgdorferi N40 that appears to contain a single gene that may be a homolog of erpG. Three OspEF-related loci (bbk2.10, bbk2.11, and ospF) have been identified in B. burgdorferi isolate 297 (1).…”

“…Such rearrangements may serve to prevent the bacteria from being immediately recognized and cleared by the immune systems of previously infected mammals. Several reports indicate that at least some of the OspEF-related proteins are antigenic in infected humans and laboratory animals (1,26,32,(49)(50)(51). The pres- ence within a single bacterium of a number of different genes encoding OspEF-related proteins may also allow sequential expression of the proteins during the course of mammalian infection.…”

Borrelia burgdorferi complement regulator-acquiring surface proteins (BbCRASPs): Expression patterns during the mammal–tick infection cycle

“…Transcripts from erp genes have been detected in various tissues of infected laboratory animals, including non-human primates, throughout the course of disseminated and persistent infection . B. burgdorferi-infected mice mount rapid antibody responses to Erp proteins Akins et al, 1995;Suk et al, 1995;Wallich et al, 1995;Stevenson et al, 1998;Miller et al, 2000b;Hefty et al, 2001Hefty et al, , 2002McDowell et al, 2001). Erp-directed antibodies persist at high levels and periodically increase during prolonged infection, suggesting sustained exposure (and re-exposure) to Erp proteins throughout chronic infection .…”

A new animal model for studying Lyme disease spirochetes in a mammalian host-adapted state.

“…Of these, Lp6.6 is thought to be specific for the arthropod phase of the enzootic cycle (Schoeler, G.B., and S.K. Wikel, unpublished observations), whereas the others appear to be expressed exclusively during mammalian infection (9)(10)(11)(12)(13)(14).…”