Borrelia burgdorferi erpT expression in the arthropod vector and murine host

Abstract

SummaryThe expression of a Borrelia burgdorferi gene, erpT, was investigated throughout the spirochaete life cycle in the arthropod vector and the murine host. Three phage clones from a B. burgdorferi DNA expression library synthesized a 30 kDa antigen that was recognized by antibodies in the sera of B. burgdorferiinfected mice but not mice hyperimmunized with B. burgdorferi lysates. Differential antibody binding suggested that this protein was preferentially expressed in vivo. This antigen was designated ErpT, based upon 99.6% homology with the BBF01 sequence in the B. burgdorferi genome. ErpT was not detected on spirochaetes cultured in BSK II medium by indirect immunofluorescence or in B. burgdorferi lysates by immunoblotting, implying that ErpT is not readily produced in vitro. erpT mRNA was not discernible by Northern blot but was identified by RNA polymerase chain reaction in vitro, indicating that erpT is expressed at low levels by cultured spirochaetes. erpT expression was then investigated in the vector and mice because B. burgdorferi do not normally reside in culture medium. RNA polymerase chain reaction and immunofluorescence studies demonstrated that erpT was expressed by a small minority of B. burgdorferi (11/500, 2.2%) within unfed ticks and then repressed during engorgement. erpT mRNA or ErpT antibodies were first detected in B. burgdorferi-infected mice at 4 weeks, suggesting that erpT was not expressed in the early stages of murine infection. Then, during persistent infection, RNA polymerase chain reaction showed that erpT was expressed by B. burgdorferi within the joints, heart and spleen, but not by spirochaetes in the skin. Immunization of mice with ErpT was antigenic but was not protective. These studies demonstrate that B. burgdorferi erpT is differentially expressed throughout the B. burgdorferi life cycle, in both the vector and the mammalian host, and is primarily expressed in extracutaneous sites during murine infection.

Inhibition of Borrelia burgdorferi-Tick Interactions In Vivo by Outer Surface Protein A Antibody

“…22). Rabbit antisera against recombinant OspA-, OspF-, and OspE-related protein (Erp) T from B. burgdorferi N40 have been described previously by our group (16,28,29). OspF is encoded by a member of a multigene family (erps) that are differentially expressed throughout the B. burgdorferi life cycle (30).…”

“…OspF is encoded by a member of a multigene family (erps) that are differentially expressed throughout the B. burgdorferi life cycle (30). B. burgdorferi erpT is preferentially expressed in vivo, and antiserum directed against ErpT is not borreliacidal (28).…”

Arthropod- and Host-Specific Borrelia burgdorferi bbk32 Expression and the Inhibition of Spirochete Transmission

“…For quantitative PCR, a competition assay was performed based on established techniques (12,39). Competitor constructs were created in which a 540-bp fragment of unrelated DNA was flanked by the flaB, bbk32, or bbk50 primers.…”

“…1) and then at different disseminated sites on days 14, 30, and 60, intervals that reflect the various stages of disease (Table I). flaB mRNA, which is constitutively expressed, was used for comparison (12). Representative examples of the flaB, bbk32, and bbk50 quantitative RT-PCR are shown in Fig.…”

Dissociation of Infectivity and Pathogenicity in Borrelia burgdorferi

“…Previous studies have shown that infectivity does not correlate strictly with the presence of ospD (15,(19)(20)(21). We therefore assessed whether erpT, a gene that is preferentially expressed in deep tissues and is present on the vls-containing plasmid lp28-1, was present in N40-120 (10,12,13). erpT DNA was not detected in N40-120 (Fig.…”