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

Abstract

Antisera to BBK32 (a Borrelia burgdorferi fibronectin-binding protein) and BBK50, two Ags synthesized during infection, protect mice from experimental syringe-borne Lyme borreliosis. Therefore, B. burgdorferi bbk32 and bbk50 expression within Ixodes scapularis ticks and the murine host, and the effect of BBK32 and BBK50 antisera on spirochetes throughout the vector-host life cycle were investigated. bbk32 and bbk50 mRNA and protein were first detected within engorged ticks, demonstrating regulated expression within the vector. Then bbk32 expression increased in mice at the cutaneous site of inoculation. During disseminated murine infection, bbk32 and bbk50 were expressed in several murine tissues, and mRNA levels were greatest in the heart and spleen at 30 days. BBK32 antisera protected mice from tick-borne B. burgdorferi infection and spirochete numbers were reduced by 90% within nymphs that engorged on immunized mice. Moreover, 75% of these ticks did not retain spirochetes upon molting, and subsequent B. burgdorferi transmission by adult ticks was impaired. Larval acquisition of B. burgdorferi by I. scapularis was also inhibited by BBK32 antisera. These data demonstrate that bbk32 and bbk50 are expressed during tick engorgement and that BBK32 antisera can interfere with spirochete transmission at various stages of the vector-host life cycle. These studies provide insight into mechanisms of immunity to Lyme borreliosis and other vector-borne diseases.

Lyme Borreliosis - the Utility of Improved Real-Time PCR Assay in Detection of Borrelia burgdorferi Infections

“…[26,27]. The line blot tests confirmed that more than 8% of the positive results of the ELISA in class IgG and [30,[32][33][34][35][36]. Therefore, many false positive results may appear during in ELISA/line blot test and detection of bacteria genomic DNA may play an important role in the diagnosis of Borrelia infections.…”

The Complement Regulator Factor H Binds to the Surface Protein OspE of Borrelia burgdorferi

“…P35/BBK32 has been described to raise a protective antibody response in mice after vaccination (9). Later, this protein was characterized as a fibronectin-binding protein (55,56). The importance of P35/ BBK32 binding to factor H requires further studies because when P35/BBK32 was immobilized on the sensor chip, it did not bind factor H anymore.…”

Improved serodiagnosis of erythema migrans using novel recombinant borrelial BBK32 antigens

“…Expression of bbk32 is detectable in spirochaetes during tick feeding even before transmission to the host (Fikrig et al, 2000). Thus if the spirochaetes gain access to the skin of a human, there may be an early antibody response.…”